WO2013038134A1 - Synthesis and anticancer activity of ruthenium (11) cis-cis-1,3,5- triaminocyclohexane complexes - Google Patents

Synthesis and anticancer activity of ruthenium (11) cis-cis-1,3,5- triaminocyclohexane complexes Download PDF

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WO2013038134A1
WO2013038134A1 PCT/GB2012/000723 GB2012000723W WO2013038134A1 WO 2013038134 A1 WO2013038134 A1 WO 2013038134A1 GB 2012000723 W GB2012000723 W GB 2012000723W WO 2013038134 A1 WO2013038134 A1 WO 2013038134A1
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cancer
ruthenium
alkyl
cis
complex
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PCT/GB2012/000723
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French (fr)
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Aimee Joanna GAMBLE
Jason Martin LYNAM
Paul Howard Walton
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University Of York
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F15/00—Compounds containing elements of Groups 8, 9, 10 or 18 of the Periodic Table
    • C07F15/0006—Compounds containing elements of Groups 8, 9, 10 or 18 of the Periodic Table compounds of the platinum group
    • C07F15/0046—Ruthenium compounds
    • C07F15/0053—Ruthenium compounds without a metal-carbon linkage
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P35/00—Antineoplastic agents
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F15/00—Compounds containing elements of Groups 8, 9, 10 or 18 of the Periodic Table
    • C07F15/0006—Compounds containing elements of Groups 8, 9, 10 or 18 of the Periodic Table compounds of the platinum group
    • C07F15/0046—Ruthenium compounds
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F17/00—Metallocenes
    • C07F17/02—Metallocenes of metals of Groups 8, 9 or 10 of the Periodic System

Definitions

  • the present invention relates to novel therapeutically active agents and to processes for the preparation thereof.
  • the invention relates to novel ruthenium ( ⁇ ) cis-cis- 1,3,5- triaminocyclohexane (tach) complexes and to their use and methods for treating proliferative pathologies, in particular cancers, and to methods for the preparation thereof.
  • Cancer is a disease which is defined by two properties: uncontrollable growth, where cells divide beyond the normal restraints of a cell, and - when malignant - invasion into, and the destruction of either surrounding tissues or other locations in the body from via the lymph or blood. Most cancers are tumours (solid growths), however some cancers, such as leukaemia, are not.
  • a single genetic mutation in the replication of a cell is insufficient to cause uncontrollable cancerous growth.
  • a series of independent mutations must occur, all within the lineage of a single cell, and these mutations must overcome natural selection and cell control mechanisms, accounting for the low incidence of cancers compared to the number of expected mutations within a lifetime.
  • Such a requirement for multiple mutations accounts for the increased incidence of cancer with age, where cells have undergone more cell divisions, and therefore a higher chance of mutation. Cancers are rarely diagnosed within the early stages of mutations, and are only detectable when they reach advanced stages, such as invasive carcinomas.
  • cisplatin II Since global approval in 1979, cisplatin II has become a significant tool in the treatment of lung, testicular, ovarian and bladder cancers as the only transition metal- based chemotherapeutic in clinical use for cancer treatment under the trade name of Platinol®.
  • the potential of cisplatin as an anticancer agent after its initial discovery in 1845 was only realised by Rosenberg in 1965 when the serendipitous production of cisplatin at a platinum electrode inhibited the growth of E-coli bacteria.
  • Carboplatin 12 and oxaloplatin 13 are both aquation resistant due to the chelating ligand, and therefore undergo ligand exchange much more slowly than cisplatin II. This effect accounts for the greatly reduced general toxicity of these complexes and reduced side effects, from the reduced levels of active drug in the kidneys and gastrointestinal tract. 3
  • Platinum drugs are significantly associated with severe side effects, from the poor selectivity for cancer cells and toxicity to all cells - including healthy cells. 8 ' 9 Platinum resistance, both primary and acquired, limits the use of these drugs.
  • ruthenium the most promising alternative for platinum as a cancer chemotherapy treatment which reduces the undesired properties of cisplatin based drugs is ruthenium. 10"15 Ligand exchange kinetics for ruthenium complexes are similar to those observed with platinum in aqueous solution, occurring much more slowly when compared to other metal complexes, a key property in anticancer activity. Ruthenium is known to be systematically less toxic than platinum, possibly through ruthenium's ability to mimic iron in a biological environment, 16 Cellular uptake of iron occurs through binding to serum transferrin and albumin proteins, which solubilise and transport the metal ions in plasma.
  • FIG. 3 NAMI-A and KP1019, the only two ruthenium complexes to reach clinical trials for use in anticancer therapy.
  • NAMI-A is still in a phase ⁇ study, and a phase ⁇ study with KP1019 for use in patients with advanced colorectal cancer is being planned.
  • the ruthenium (HI) species described are relatively unreactive in the +3 oxidation state in normal, oxidizing tissue. It is only when reduction occurs to ruthenium ( ⁇ ) in hypoxic conditions found in tumours, as explained by Clarke in the "activation by reduction” theory, that the complexes become biologically active. 21 Therefore, it is believed that the ruthenium ( ⁇ ) complexes are pro-drugs to the active ruthenium (II) species. Studies show that NAMI-A, reduced by ascorbic acid to ⁇ - ⁇ , prior to administration proved to be significantly more efficient than the parent complex, which is in accordance with Clarke's theory. 22
  • the lead complex from the initial report consisting of biphenyl as the >7 6 -arene, ethylenediamine as the chelating ligand and chloride as the leaving group, 19, was found to be equipotent to carboplatin in A2780 human ovarian cancer cells.
  • the p- cymene analogue 110 was also equipotent with carboplatin. Employment of un- substituted benzene in 111 further reduced activity. It was later reported that use of highly extended aromatics, such as tetrahydroanthrocene in 112 exhibited greater activity than 19, equipotent to cisplatin.
  • the complexes do not inhibit topoisomerase enzymes which are involved in DNA replication; however they do form strong interactions with the guanine base in DNA, providing the drug directly targets DNA, in a similar way to cisplatin. 25 ' 26
  • Table 1 Prototype ruthenium ethylenediamine complexes by Sadler and coworkers, with IC50 values for A2780 and cross resistance profiles, compared to cisplatin and carboplatin.
  • 19 binds to a single guanine-N7 residue, and forms a stabilised complex through a hydrogen bond between the ethylenediamine N-H and the guanine- 06, possibly accounting for the unique cross resistance profile and a different method of inhibiting cell replication once bound to DNA.
  • Table 3 Cytotoxic activity for complexes containing terphenyl ligands, with ICso values for the A2780, CHI ovarian carcinoma and SKBR3 mammary carcinoma cell lines.
  • N,0- chelating ligands such as amino acids and 8-hydroxyquinoline, possessed no activity towards A2780 (IC 5 o > 100 ⁇ in all cases), thought to be due to deactivation under biological conditions despite demonstrating fast aquation kinetics and strong binding to 9-ethylguanine.
  • 27 Ruthenium ( ⁇ ) arene complexes, containing f-l,3,5-triaza-7-phosphatricyclo- [3.3.1.1]decanephosphine (PTA), termed 'RAPTA' were initially reported in 2001.
  • Figure 8 [9]aneS 3 analogues of ruthenium arene complexes which show anticancer activity.
  • WO 01/10870 (Brechbiel & Planalp) describes transition metal complexes of ⁇ , ⁇ ', ⁇ ''-trialkyl- cis,cis-l,3,5-triaminocyclohexanes.
  • WO 0'870 focuses on the delivery of copper complexes for imaging agents and does describes complexes for use as therapeutic agents.
  • International Patent application No. WO 2006/016069 (Pfeffer) describes ruthenium complexes for treating cancers.
  • the complexes described in WO ⁇ 69 suffer from poor water solubility and are generally associated with therapeutically unacceptable anions, such as, hexafluorophosphate.
  • hexafluorophosphate salts are often advantageous as an inert and non-coordinating counter ion in solvolysis, the anion is slow to hydrolyse and is unsuitable for use in a therapeutically active agent.
  • WO '069 does not disclose cis-cis- 1,3,5-triaminocyclohexane complexes.
  • WO 2011/001109 also describes ruthenium complexes for treating cancers, but again the complexes described are generally associated with the therapeutically unsuitable hexafluorophosphate anion and the complexes suffer from poor water solubility.
  • WO '109 does not disclose cis- cis- 1,3,5-triaminocyclohexane complexes. Therefore, there is a need for novel anticancer agents which could be an alternative to those currently used and/or which would have minimal undesirable side effects and/or improved aqueous solubility.
  • the cis-cis- 1,3,5-triaminocyclohexane ligand, cw-tach, has been widely used with first row transition metals in complex design, for many applications.
  • Figure 10 cis-cts-l,3,5-triaminocyclohexane (crs-tach). When bound to a metal centre, the amino groups adopt an axial conformation.
  • the ligand which when bound to a metal centre forms an adamantine-like structure, has applications include use as a building block in coordination clusters, 36 RNA and DNA cleavage, 37"39 catalysis, 40 radiopharmaceuticals, 1, 2 anticancer agents, 43"45 and the mimicking of transition metal biomolecules for their study. 46 ' 47
  • cw-tach is a /ac-coordinating ligand, it can therefore be compared to the half sandwich complexes reported by Dyson and Sadler.
  • the cyclohexane ring in m-tach may act as a hydrophobic face to the complex, whereas the amine groups will serve to produce a hydrophilic metal centre, and aid water solubility through hydrogen bonds.
  • Figure 11 General structure of ruthenium (II) cis-tach complexes with chloride leaving group and a chelating ligand. Charges are omitted for clarity.
  • Ruthenium ( ⁇ ) cis-tach complexes with a chloride ligand, will be structurally similar to cisplatin, however more closely related to oxaloplatin with the bidentate trans-1,2- diaminocyclohexane. Therefore, the cis-tach complexes may be closer in their chemistry to the proven cisplatin complexes, and possess greater activity.
  • the amine groups of cis-tach also resemble those in Sadler's half-sandwich ethylenediamine complexes, where an amine ligand is adjacent to the chloride ligand, and ultimately, the DNA upon coordination.
  • the functionality of this important ligand is incorporated into the ⁇ ac-coordinating ligand, leaving two vacant coordination sites, occupied by a chelating ligand, for example.
  • This chelating ligand can be altered to infer different electronic properties onto the metal, additional hydrophobic groups to change lipophilicity, or by addition of groups to aid water solubility.
  • the present invention proposes ruthenium complexes which have, inter alia, beneficial antitumour properties and/or improved aqueous solubility over known prior ruthenium or platinum therapeutic agents. Therefore, according to a first aspect of the invention there is provided a complex of formula I:
  • R 1 , R 2 , R 3 , R 4 , R 5 and R 6 which may be the same or different are each, hydrogen or alkyl CI to 20, alkenyl CI to 20, aryl, alkyl (C j (0 20)aryl, alkenyl (C i to 20)aryl, heteroaryl, a sugar, an amino acid, a nucleoside, a nucleotide or a peptide;
  • R 7 , R 8 and R 9 which may be the same or different are each, hydrogen or alkyl CI to
  • L 1 , L 2 and L 3 which may be the same or different, are each selected from the group comprising halogen (halogen may optionally be a bridging moiety between two groups of formula I), -PR 10 R U R 12 , -NCR 13 , -S(0)R 14 R 15 ; or
  • a pair of any two of L 1 , L 2 and L 3 may comprise a moiety -R 16 R 17 N-(CHR 18 ) n -
  • a pair of any two of L 1 , L 2 and L 3 may comprise a moiety of formula VI; a pair of any two of L 1 , L 2 and L 3 may comprise a C6 to 20 cycloalkyldiene; L 1 , L 2 and L 3 may together form a 6- to 8- membered arene;
  • n and m which may be the same or different, are each an integer 1 to 6
  • R 11 and R 12 which may be the same or different, are each alkyl CI to 20 or aryl optionally substituted by one or more alkyl CI to 20;
  • R 13 , R 14 and R 15 which may be the same or different, are each alkyl CI to 20 or aryl optionally substituted by one or more alkyl CI to 20;
  • R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 and R 25 which may be the same or different, are each alkyl CI to 20 or aryl optionally substituted by one or more alkyl CI to 20; any adjacent pair of R 18 or R 23 may together form a bond;
  • R 26 and R 27 which may be the same or different, are each hydrogen, alkyl CI to 20 or R 26 and R 27 together form an optionally aromatic ring;
  • the valency of the complex of formula I may vary depending upon the nature of the ligands and may be +1 or +2 (charges are omitted for clarity). Consequently, in the salt form of the complex of formula I the counter ion may be a monovalent anion or a bivalent anion or more than one monovalent anion may be present.
  • a preferred group of complexes which may be mentioned is the group of complexes of formula I in which R 1 , R 2 , R 3 , R 4 , R 5 and R 6 , which may be the same or different, are each, hydrogen or alkyl CI to 20, alkenyl CI to 20, aryl, alkyl (C i t0 20)aryl, alkenyl (C1 to 20>aryl or heteroaryl.
  • R 1 , R 2 , R 3 , R 4 , R 5 and R 6 which may be the same or different, are each, hydrogen or alkyl CI to 20, alkenyl CI to 20, aryl, alkyl (C i t0 20)aryl, alkenyl (C1 to 20>aryl or heteroaryl.
  • a preferred group of complexes which may be mentioned is the group of complexes of formula I in which R 1 , R 2 , R 3 , R 4 , R 5 and R 6 , which may be the same or different, are
  • R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , m and n are each as hereinbefore defined.
  • R 18 and 23 are each preferably hydrogen.
  • a further preferred group of complexes which may be mentioned is the group of complexes of formula I in which a pair of L l , L 2 and L 3 , represent a moiety -R 21 R 22 P- (CHR 23 ) m -PR 24 R 25 ,
  • R 2 is hydrogen.
  • R 21 , R 22 , R 24 and R 25 are each aryl, e.g. phenyl.
  • m is an integer from 1 to 4.
  • R 1 , R 3 and R 5 are each hydrogen.
  • R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each hydrogen.
  • R 7 , R 8 and R 9 are each hydrogen.
  • R 26 and R 27 are preferably the same and may each be hydrogen, to provide a ligand of formula Via, or R 26 and R 27 together form an aromatic ring, to provide a ligand of formula Vlb:
  • L 1 , L 2 and L 3 represent a C6 to 20 cycloalkyldiene
  • a preferred moiety is a cyclooctadiene, e.g. T
  • L 1 , L 2 and L 3 which may be the same or different, are each selected from the group comprising halogen (halogen may optionally be a bridging moiety between two groups of formula I), -PR'°R"R 12 , -NCR 13 ; or
  • a pair of any two of L 1 , L 2 and L 3 may comprise a moiety -R 16 R I7 N-(CHR I8 )n-
  • a pair of any two of L l , L 2 and L 3 may comprise a moiety of formula VI; a pair of any two of L 1 , L 2 and L 3 may comprise a C6 to 20 cycloalkyldiene L 1 , L 2 and L 3 may together form a 6- to 8- membered arene.
  • alkyl refers to a fully saturated, branched or unbranched hydrocarbon moiety, i.e. primary, secondary or tertiary alkyl or, where appropriate, cycloalkyl or alkyl substituted by cycloalkyl, they may also be saturated or unsaturated alkyl groups. Where not otherwise identified, preferably the alkyl comprises 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, 1 to 10 carbon atoms, 1 to 7 carbon atoms, or 1 to 4 carbon atoms.
  • alkyl include, but are not limited to, methyl, ethyl, «-propyl, iro-propyl, «-butyl, sec-butyl, wo-butyl, ferf-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl, 2,2- dimethylpentyl, 2,3-dimethylpentyl, #-heptyl, «-octyl, n-nonyl, rc-decyl and the like.
  • cycloalkyl refers to saturated or unsaturated monocyclic, bicyclic or tricyclic hydrocarbon groups of 3-12 carbon atoms, preferably 3-9, or 3-7 carbon atoms, each of which can be optionally substituted by one, or two, or three, or more substiruents, such as alkyl, halo, oxo, hydroxy, alkoxy, alkyl-C(O)-, acylamino, carbamoyl, alkyl-NH--, (alkyl ⁇ N--, thiol, alkyl-S--, nitro, cyano, carboxy, alkyl-O- C(0)-, sulfonyl, sulfonamide, sulfamoyl, heterocyclyl and the like.
  • Exemplary monocyclic hydrocarbon groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl and cyclohexenyl and the like.
  • Exemplary bicyclic hydrocarbon groups include bornyl, indyl, hexahydroindyl, tetrahydronaphthyl, decahydronaphthyl, bicyclo[2.1.1]hexyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.
  • aryl refers to an aromatic carbocyclic ring system containing 6 to 14 ring carbon atoms, which may be unsubstituted or substituted as defined.
  • a preferred aryl moiety is phenyl, i.e. unsubstituted phenyl.
  • heteroaryl refers to a 5-14 membered monocyclic- or bicyclic- or polycyclic-aromatic ring system, having 1 to 8 heteroatoms selected from N, 0 or S.
  • the heteroaryl is a 5-10 or 5-7 membered ring system.
  • Typical heteroaryl groups include 2- or 3-thienyl, 2- or 3-furyl, 2- or 3-pyrrolyl, 2-, 4-, or 5- imidazolyl, 3-, 4-, or 5- pyrazolyl, 2-, 4-, or 5-thiazolyl, 3-, 4-, or 5-isothiazolyl, 2-, 4-, or 5-oxazolyl, 3-, 4-, or 5-isoxazolyl, 3- or 5-1,2,4-triazolyl, 4- or 5-1,2, 3-triazolyl, tetrazolyl, 2-, 3-, or 4-pyridyl, 3- or 4-pyridazinyl, 3-, 4-, or 5-pyrazinyl, 2-pyrazinyl, 2-, 4-, or 5-pyrimidinyl.
  • heteroaryl also refers to a group in which a heteroaromatic ring is fused to one or more aryl, cycloaliphatic, or heterocyclyl rings, where the radical or point of attachment is on the heteroaromatic ring.
  • Non-limiting examples include but are not limited to 1-, 2-, 3-, 5-, 6-, 7-, or 8- indolizinyl, 1-, 3-, 4-, 5-, 6-, or 7-isoindolyl, 2-, 3-, 4-, 5-, 6-, or 7-indolyl, 2-, 3-, 4-, 5-, 6-, or 7-indazolyl, 2-, 4-, 5-, 6-, 7-, or 8- purinyl, 1-, 2-, 3-, 4-, 6-, 7-, 8-, or 9-quinolizinyl, 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolinyl, 1-, 3-, 4- , 5-, 6-, 7-, or 8-isoquinolinyl, 1-, 4-, 5-, 6-, 7-, or 8-phthalazinyl, 2-, 3-, 4-, 5-, or 6- naphthyridinyl, 2-, 3-, 5-, 6-, 7-, or 8-quinazolinyl, 3-, 4-, 5-, 6-, 7-
  • 6- , 7-, or 8-carbazolyl 1-, 3-, 4-, 5-, 6-, 7-, 8-, or 9-carbolinyl, 1-, 2-, 3-, 4-, 6-, 7-, 8-, 9-, or 10-phenanthridinyl, 1- , 2-, 3-, 4-, 5-, 6-, 7-, 8-, or 9-acridinyl, 1-, 2-, 4-, 5-, 6-,
  • Typical fused heteroaryl groups include, but are not limited to 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolinyl, 1-, 3-, 4-, 5-, 6-, 7-, or 8- isoquinolinyl, 2-, 3-, 4-, 5-, 6-, or 7-indolyl, 2-, 3-, 4-, 5-, 6-, 7-benzofuranyl, 2-, 4-, 5- , 6-,or 7-benzo[bJthienyl, 2-, 4-, 5- , 6-, or 7-benzoxazolyl, 2-, 4-, 5-, 6-, or 7- benzimidazolyl, 2-, 4-, 5-, 6-, or 7-benzothiazolyl.
  • a heteroaryl group may be mono-, bi-, tri- or polycyclic, preferably mono-, bi-, or tricyclic, more preferably mono- or bicyclic.
  • halogen refers to fhioro, chloro, bromo, and iodo.
  • sugar may mean a natural or a synthetic sugar. Sugars that may be mentioned include, but shall not be limited to, glucose, glucosamine, glucuronic acid, ribose, and 2-deoxy derivatives thereof, e.g. 2-deoxy glucose, 2-deoxy-2-fluoro glucose and 2-deoxy ribose; and derivatives thereof.
  • amino acid used herein include, but shall not be limited to, alanine, arginine, asparagines, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, ornithine, phenylalanine, proline, selenocysteine, serine, taurine, threonine, tryptophan, tyrosine and valine; and derivatives thereof.
  • amino acid refers to a naturally occurring a-amino acid and their stereoisomers, as well as non-natural amino acids such as amino acid analogues, synthetic amino acids, ⁇ -amino acids, ⁇ -amino acids, N-methyl amino acids, and N-substituted glycines, in either the L- or D-configuration that function in a manner similar to the naturally occurring amino acids.
  • “Stereoisomers” of naturally occurring amino acids refers to mirror image isomers of the naturally occurring amino acids, such as D-amino acids.
  • amino acid analogues refers to compounds that have the same basic chemical structure as naturally occurring amino acids, e.g.
  • peptide refers to a compound made up of a single chain of D- or L-amino acids or a mixture of D- and L-amino acids joined by peptide bonds.
  • peptides are from about 2 to about 50 amino acids in length.
  • the peptides of the present invention may be preferably from about 2 to about 25 amino acids, more preferably from about 2 to about 10 amino acids, and most preferably from about 2 to 8 amino acids in length.
  • the free amino-terminus and/or carboxyl-terminus on the peptides may optionally be protected by an amide, an alkyl, e.g. methyl, ester, a succinyl, or an acetyl group. Further chemical modifications may also be contemplated.
  • nucleoside shall include, but shall not be limited to, naturally occurring nucleosides, such as, adenosine, guanosine, cytidine, thymidine, and uridine; and modifications thereof. Modifications shall include, but shall not be limited to, those providing chemical groups that incorporate additional charge, polarisability, hydrogen bonding, and electrostatic interaction to the nucleosides.
  • nucleosides may also include non-natural bases, such as, nitroindole, 5-aza-cytidine, 5-aza-2'- deoxycytidine, and dihydro-5-aza-2'-deoxycytidine; and modifications thereof.
  • nucleotides shall mean are phosphate esters of nucleosides as hereinbefore defined. Thus, many of the chemical reactions which are utilised for nucleosides can also be utilised for nucleotides. It will be understood by the person skilled in the art that the aforementioned sugars, amino acids, peptides, nucleosides and/or nucleotides may be coordinated to a ruthenium moiety via one or more of nitrogen or a carboxying group. Specific complexes of formula I which may be mentioned include:
  • the complexes of the invention are advantageous in the treatment or alleviation of disorders linked to cell hyperproliferation, in particular cancers, e.g. apoptosis of cancer cells.
  • cancers include those with solid or liquid tumours.
  • cancers may be mentioned which include, but shall not be limited to one or more of primary cancer, breast cancer, colon cancer, prostate cancer, non-small cell lung cancer, glioblastoma, lymphoma, mesothelioma, liver cancer, intrahepatic bile duct cancer, oesophageal cancer, pancreatic cancer, stomach cancer, laryngeal cancer, brain cancer, ovarian cancer, testicular cancer, cervical cancer, oral cancer, pharyngeal cancer, renal cancer, thyroid cancer, uterine cancer, urinary bladder cancer, hepatocellular carcinoma, thyroid carcinoma, osteosarcoma, small cell lung cancer, leukaemia, myeloma, gastric carcinoma and metastatic cancers.
  • the complexes are advantageous in the treatment or alleviation of a metastatic cancer.
  • a complex of formula I as hereinbefore described in the manufacture of a medicament. More particularly, we provide the use as hereinbefore described in the manufacture of a medicament for the treatment of a proliferative disorder.
  • a complex of formula I as hereinbefore described in the manufacture of a medicament in the form of an aqueous solution.
  • a method of treatment or alleviation of a proliferative disorder which comprises administering to a mammal a therapeutically effective amount of a complex of formula I as hereinbefore described, or a salt thereof.
  • the method of treatment or alleviation of a proliferative disorder may comprise preparing an aqueous solution of a complex of formula I of the invention.
  • a low chloride concentration (of less than 5 mmol) at physiological pH (typically 6.5 to 7.4) to simulate a cell
  • a high chloride concentration 100 mmol to replicate the blood, where anation is dominant and the parent chloride species persists.
  • Figure 134-2b herein is a ⁇ 5 H ⁇ 3I P NMR spectrum of the equilibrium.
  • the additional signals in Figure 12b were attributed to the resultant guanosine complex - [RuCl(dppe)(Guo)(tach)]2Cl, observed as two doublets, arising from the lack of symmetry induced onto the ruthenium centre from the chiral sugar of guanosine.
  • the lack of the symmetry results in the two phosphorus nuclei of the dppe ligand to become inequivalent, exhibit a different chemical shift to each other and to couple through and 4 J coupling.
  • the species are observed in the ratio of 24.4% chloro, 30.5% aqua hydroxy and 45.1% guanosine adduct.
  • the proposed structure of the resulting guanosine complex is depicted in figure 13, with the nucleobase bound to the ruthenium through the N7, as observed with other metallodrugs.
  • the 06 of the guanosine base is likely to form a hydrogen bond to the N3 ⁇ 4 group of the cis-tach ligand
  • the complex is proposed to be structurally similar to the corresponding case with [RuCl(dppe)(tach][Cl], [15](C1], with coordination by the N7 and an NH-06 hydrogen bond present between the cw-tach N3 ⁇ 4 protons and guanosine.
  • Figure 1 Proposed structure for [Ru(Guo)(phen)(cw-tach)] , with NH-0 hydrogen bond between cw-tach and guanosine.
  • R ribose of guanosine.
  • the activity of a complex according to the present invention can be assessed by the following in vitro ⁇ in vivo methods.
  • the MTT assay is a colourimetric assay used to determine the cytotoxicity of a compound.
  • Cells are treated with various concentrations of drug, typically ranging between 0.1 and 300 uM, with positive (no ceils added, 0% viability) and negative (untreated cells, J 00% viability) controls.
  • the water soluble MTT dye is added and viable cells allowed to metabolize the MTT to insoluble purple formazan crystals.
  • the activity of the compound is calculated as the IC50 - the concentration of drug required to inhibit MTT formazan production by 50 % , and thus to inhibit the growth of cells by 50 %, through a dose-response curve, with each value at a given concentration calculated as a percentage of cell viability compared to the positive and negative controls.
  • MTT assays were performed using the A549 human non-small cell lung adenocarcinoma and A2780 human ovarian adenocarcinoma cell lines. Both cell lines are available from the European Collection of Cell Cultures (ECACC), Health Protection Agency. Specific methodology for conducting the assays is referred to in the examples herein.
  • compositions comprising a complex of formula I as hereinbefore described, in free form or in pharmaceutically acceptable salt form, in association with a pharmaceutically acceptable adjuvant, diluent or carrier.
  • the pharmaceutical compositions for separate administration of the combination partners and for the administration in a fixed combination, i.e., a single galenical composition comprising at least two combination partners, according to the invention can be prepared in a manner known per se and are those suitable for enteral, such as oral or rectal, and parenteral administration to mammals, including man, comprising a therapeutically effective amount of at least one pharmacologically active combination partner alone or in combination with one or more pharmaceutically acceptable carriers, especially suitable for enteral or parenteral application.
  • compositions contain, e.g., from about 0.1% to about 99.9%, preferably from about 20% to about 60%, of the active ingredients.
  • Pharmaceutical preparations for the combination therapy for enteral or parenteral administration are, e.g., those in unit dosage form, such as tablets including sugar-coated tablets, capsules, suppositories and ampoules. These are prepared in a manner known, per se, e.g., by means of conventional mixing, granulating, sugar-coating, dissolving or lyophilizing processes. It will be appreciated that the unit content of a combination partner contained in an individual dose of each dosage form need not in itself constitute an effective amount since the necessary effective amount can be reached by administration of a plurality of dosage units.
  • the pharmaceutical composition can be formulated for particular routes of administration such as oral administration, parenteral administration, and rectal administration, etc.
  • the pharmaceutical compositions of the present invention can be made up in a solid form including capsules, tablets, pills, granules, powders or suppositories, or in a liquid form including solutions, suspensions or emulsions.
  • the pharmaceutical compositions can be subjected to conventional pharmaceutical operations such as sterilization and/or can contain conventional inert diluents, lubricating agents, or buffering agents, as well as adjuvants, such as preservatives, stabilizers, wetting agents, emulsifiers and buffers etc.
  • compositions are aqueous isotonic solutions or suspensions, and suppositories are advantageously prepared from fatty emulsions or suspensions.
  • Said compositions may be sterilized and/or contain adjuvants, such as preserving, stabilizing, wetting or emulsifying agents, solution promoters, salts for regulating the osmotic pressure and/or buffers. In addition, they may also contain other therapeutically valuable substances.
  • Said compositions are prepared according to conventional mixing, granulating or coating methods, respectively, and contain about 0.1-75%, or contain about 1-50%, of the active ingredient.
  • the pharmaceutical composition according to this aspect of the invention is in the form of an aqueous solution.
  • the appropriate dosage will of course vary depending upon, for example, the complex employed, the host, the mode of administration and the nature and severity of the condition being treated. However, in general, satisfactory results in animals are indicated to be obtained at a daily dosage of from about 0.1 to about 100 mg kg, preferably from about 1 to about 30 mg/kg animal body weight. In larger mammals, for example humans, an indicated daily dosage is in the range from about 1 to about 500 mg, preferably from about 1 to about 100 mg of an agent of the invention, conveniently administered, for example, in divided doses up to three times a day or in sustained release form.
  • the complexes or compositions of the invention may be administered by any conventional route, in particular enterally, preferably orally, for example in the form of tablets or capsules, or parenterally, for example in the form of injectable solutions or suspensions.
  • the complexes according to the invention have an antiproliferative effect with respect to tumoral cells. They are useful for treating cancers by inducing apoptosis in tumoral cells.
  • the complexes according to the invention are particularly advantageous for treating tumours which are resistant to cisplatinum or to other anticancer drugs.
  • the complexes or compositions according to the invention can be administered in different ways and in different forms. Therefore, they can be administered systemically, orally, by inhalation or by injection, for example intravenously, intramuscularly, subcutaneously, transdermically, intra-arterially, etc., the intravenous, intramuscular, subcutaneous, oral and inhalation methods being preferred.
  • the complexes are generally conditioned in the form of liquid suspensions, which can be injected by means of syringes or perfusions, for example.
  • the complexes of the invention are significantly more water soluble than other anticancer drugs, such as, cisplatin, and may generally be dissolved in saline, physiological, isotonic, buffered etc. solutions, compatible with pharmaceutical use and known to the person skilled in the art.
  • the complexes of the present invention have generally been found to be soluble at least to 1 mM in water or phosphate buffered saline (PBS) at room temperature.
  • PBS phosphate buffered saline
  • diphosphanes i.e. those in which a pair of any two of V, L 2 and L 3 comprise a moiety -R 2 ! R 22 P-(CHR 23 ) m -PR 24 R 25 , such as the dppe complex
  • the bis dmso complexes i.e. those in which at least two of L 1 , L 2 and L 3 represent -S(0)R 1 R 15 , such as chlorobis(dimethylsulfoxide-K.3 ⁇ 4(ci5 ; -ci5-1 ,5-triaminocyclohexane- ⁇ , ⁇ ', ⁇ ") ruthenium(n) chloride ([RuCl(dmso) 2 (tach)]Cl), have a solubility of greater than 300mM.
  • compositions can contain one or more agents or vehicles chosen from dispersants, solubilisers, stabilisers, preservatives, etc.
  • Agents or vehicles which can be used in liquid and/or injectable formulations are in particular methylcellulose, hydroxymethylcellulose, carboxymethylcellulose, polysorbate 80, mannitol, gelatin, , lactose, vegetable oils, acacia, etc.
  • the complexes can also be administered in the form of gels, oils, tablets, suppositories, powders, capsules, aerosols, etc., possibly by means of galenic forms or devices guaranteeing prolonged and/or delayed release.
  • an agent such as cellulose, carbonates or starches.
  • the throughput and/or the dose injected can be adapted by the person skilled in the art dependently upon the patient, the pathology in question, the administration method, etc.
  • the complexes are administered at doses which can vary between 0.1 and 100 mg/kg body weight, and more generally between 0.01 and 10 mg kg, typically between 0.1 and 10 mg/kg.
  • repeated injections can be given, should the occasion arise.
  • delay or prolongation systems can be advantageous.
  • the invention also concerns a method for treating a pathology linked to cell hyperproliferation, in particular a cancer, by administering to a subject suffering from this type of pathology an effective quantity of one of the complexes according to the invention.
  • treatment means the preventive, curative, palliative treatment as well as patient care (reduction of suffering, improvement of life span, slowing down the progression of the illness, reducing the tumoral growth, etc.).
  • treatment can be implemented in combination with other agents or chemical or physical treatments (chemotherapy, radiotherapy, gene therapy, etc.).
  • the treatments and drugs of the invention are particularly intended for humans.
  • the complexes according to the invention can advantageously be used in combination with an anti-cancer treatment implementing radiation, such as radiotherapy and brachytherapy.
  • radiation such as radiotherapy and brachytherapy.
  • the radiation applied involves in particular X rays, gamma rays, ionising particles such as electrons, neutrons or carbon ions.
  • a pharmaceutical composition comprising a complex of formula I, in free form or in pharmaceutically acceptable salt form, in combination with another therapeutically active ingredient, optionally in association with a pharmaceutically acceptable adjuvant, diluent or carrier.
  • the complexes according to the invention can be used with other chemical agents or therapeutic anti-cancer treatments, such as the following therapeutic chemical agents: cisplatinum, carboplatinum, NCS (neocarzinostatin), Taxotere ® or Taxol ® , advantageously NCS or Taxol ® .
  • the complexes according to the invention are preferably conditioned and administered in combination, separately or sequentially in relation to other agents or therapeutic treatments.
  • Complexes of the present invention may be usefully combined with another pharmacologically active compound, or with two or more other pharmacologically active compounds, particularly in the treatment of cancer.
  • a complex of the present invention may be administered simultaneously, sequentially or separately in combination with one or more agents selected from chemotherapy agents, e.g. mitotic inhibitors such as a taxane, a vinca alkaloid, paclitaxel, docetaxel, vincristine, vinblastine, vinorelbine or vinflunine, and other anticancer agents, e.g. cisplatin, 5-fluorouracil or 5-fluoro-2-4(l H, 3H)-pyrimidine dione (5FU), flutamide or gemcitabine.
  • chemotherapy agents e.g. mitotic inhibitors such as a taxane, a vinca alkaloid, paclitaxel, docetaxel, vincristine, vinblastine, vinorelbine or vinflunine
  • other anticancer agents e.g
  • a complex of the present invention may also be used to advantage in combination with other antiproliferative compounds.
  • antiproliferative compounds include, but are not limited to aromatase inhibitors; antiestrogens; topoisomerase I inhibitors; topoisomerase ⁇ inhibitors; microtubule active compounds; alkylating compounds; histone deacetylase inhibitors; compounds which induce cell differentiation processes; cyclooxygenase inhibitors; MMP inhibitors; mTOR inhibitors; antineoplastic antimetabolites; plat in compounds; compounds targeting/decreasing a protein or lipid kinase activity and further anti- angiogenic compounds; compounds which target, decrease or inhibit the activity of a protein or lipid phosphatase; gonadorelin agonists; anti-androgens; methionine aminopeptidase inhibitors; bisphosphonates; biological response modifiers; antiproliferative antibodies; heparanase inhibitors; inhibitors of Ras oncogenic isoforms;
  • tumour treatment approaches including surgery, ionizing radiation, photodynamic therapy, implants, e.g. with corticosteroids, hormones, or they may be used as radiosensitizers.
  • anti-inflammatory and/or antiproliferative treatment combination with anti-inflammatory drugs is included.
  • Combination is also possible with antihistamine drug substances, bronchodilatory drugs, NSAJD or antagonists of chemokine receptors.
  • the present invention also concerns a method for inhibiting in vivo, in vitro or ex vivo the proliferation of tumoral cells including placing said tumoral cells in contact with one of the products according to the invention.
  • the tumoral cells can in particular originate from the pathologies specified above.
  • the method may, in particular, comprise the apoptosis of tumoral cells.
  • Acid addition salts may be produced from the free bases in known manner, and vice- versa.
  • a pharmaceutically acceptable salt is any salt of the parent complex that is suitable for administration to an animal or human.
  • a pharmaceutically acceptable salt also refers to any salt which may form in vivo as a result of administration of an acid, another salt, or a prodrug which is converted into an acid or salt.
  • a salt comprises one or more ionic forms of the complex, such as a conjugate acid or base, associated with one or more corresponding counter-ions. Salts can form from or incorporate one or more deprotonated acidic groups (e.g. carboxylic acids) one or more protonated basic groups (e.g. amines), or both (e.g. zwitterions).
  • the term "pharmaceutically acceptable salts” refers to salts that retain the biological effectiveness and properties of the complexes of this invention and, which are not biologically or otherwise undesirable.
  • the complexes of the present invention are capable of forming acid and/or base salts by virtue of the presence of amino and/or carboxyl groups or groups similar thereto.
  • Pharmaceutically acceptable acid addition salts can be formed with inorganic acids and organic acids, e.g., acetate, aspartate, benzoate, besylate, bicarbonate/carbonate, bisulphate/sulphate, borate, camsylate, citrate, edisylate, esylate, formate, fumarate, gluceptate, gluconate, glucuronate, hexafluorophosphate, hibenzate, hydrochloride/chloride, hydrobromidefaromide, hydroiodide/iodide, isethionate, lactate, malate, maleate, malonate, mesylate, methylsulphate, naphthylate, 2- napsylate, nicotinate, nitrate, orotate, oxalate, palmitate, pamoate, phosphate hydrogen phosphate/dihydrogen phosphate, saccharate, stearate, succinate, tartrate, tosylate and
  • Inorganic acids from which salts can be derived include, for example, hydrochloric acid, hydrobromic acid, sulphuric acid, nitric acid, phosphoric acid, hexafluorophosphoric acid, and the like.
  • a preferred counter ion for use in association with the complex of formula I of the invention is halide, e.g. fluoride, chloride, bromide and iodide, chloride is preferred.
  • Organic acids from which salts can be derived include, for example, acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p- toluenesulfonic acid, salicylic acid, and the like.
  • Pharmaceutically acceptable base addition salts can be formed with inorganic and organic bases.
  • Inorganic bases from which salts can be derived include, for example, sodium, potassium, lithium, ammonium, calcium, magnesium, iron, zinc, copper, manganese, aluminium, and the like; particularly preferred are the ammonium, potassium, sodium, calcium and magnesium salts.
  • Organic bases from which salts can be derived include, for example, primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines, basic ion exchange resins, and the like, specifically such as isopropylamine, trimethylamine, diethylamine, triethylamine, tripropylamine, and ethanolamine.
  • the pharmaceutically acceptable salts of the present invention can be synthesized from a parent complex, a basic or acidic moiety, by conventional chemical methods.
  • a complex of the present invention can be in the form of one of the possible isomers, rotamers, atropisomers, tautomers or mixtures thereof, for example, as substantially pure geometric (cis or trans) isomers, diastereomers, optical isomers (antipodes), racemates or mixtures thereof.
  • Certain isotopically-labelled complexes of formula (I), for example, those incorporating a radioactive isotope, are useful in drug and/or substrate tissue distribution studies.
  • the radioactive isotopes tritium, i.e. 3 H, and carbon-14, i.e. C, are particularly useful for this purpose in view of their ease of incorporation and ready means of detection.
  • Substitution with heavier isotopes such as deuterium, i.e. 2 H may afford certain therapeutic advantages resulting from greater metabolic stability, for example, increased in vivo half-life or reduced dosage requirements, and hence may be preferred in some circumstances.
  • Substitution with positron emitting isotopes, such as n C, I8 F, 15 0 and 1 N can be useful in Positron Emission Topography (PET) studies for examining substrate receptor occupancy.
  • PET Positron Emission Topography
  • Isotopically-labelled complexes of formula (I) can generally be prepared by conventional techniques known to those skilled in the art or by processes analogous to those described in the accompanying Examples and Preparations using an appropriate isotopically-labelled reagents in place of the non-labelled reagent previously employed. According to an additional aspect of the invention we provide a process for the manufacture of a complex of formula I as hereinbefore described which comprises one or more of the following steps;
  • Lv, L 2 and L are each as hereinbefore defined;
  • L4 a , L 5a and L 6a are each a leaving ligand, such as halo, dmso, etc.; with a compound of formula HI;
  • R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and R 9 are each as hereinbefore defined; or (b) reacting a complex of formula IV;
  • R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and R 9 are each as hereinbefore defined; and at least one of L la , L 2a and L 3a is a leaving ligand, selected from the group consisting of halo, dmso and -PR 28 R 29 R 30 ;
  • R 28 , R 29 and R 30 which may be the same or different, are each alkyl CI to 20, aryl (optionally substituted by one or more alkyl CI to 20), amino or -OR 31 ;
  • R 31 is hydrogen or alkyl CI to 20.
  • Li a , L 2a and L 3a which may be the same or different, each have the same meaning as L 1 , L 2 and L 3 respectively or may be selected from the group consisting of halo, dmso and -PR 28 R 29 R 30 ;
  • L l3 L 2 and L 3 are each as hereinbefore defined.
  • R 1 , R 2 , R 3 , R 4 , R 5 and R 6 which may be the same or different are each, hydrogen or alkyl CI to 20, alkenyl CI to 20, aryl, alkyl(ci to 20 ) aryl, alkenyl (C] to 20 ) aryl, heteroaryl, a sugar, an amino acid, a nucleoside, a nucleotide or a peptide;
  • R 7 , R 8 and R 9 which may be the same or different are each, hydrogen or alkyl CI to 20;
  • R 28 , R 29 and R 30 which may be the same or different, are each alkyl CI to 20, aryl (optionally substituted by one or more alkyl CI to 20), amino or -OR 31 ;
  • R 31 is hydrogen or alkyl CI to 20.
  • L la , L 2a and L 3a which may be the same or different, each have the same meaning as L 1 , L 2 and L 3 respectively or may be selected from the group consisting of halo, dmso and -PR 28 R 9 R 30 ;
  • Figure 12a illustrates the ⁇ ' ⁇ 3 ⁇ NMR spectra of [15] [CI] in aqueous solution with high (top) and low (bottom) chloride levels;
  • Figure 12b illustrates the ⁇ 3 ⁇ ⁇ NMR spectrum of the equilibrium.
  • Figure 15 illustrates the DNA structural distortions from a) intrastrand 1,2 d(GpG), b) intrastrand 1,3 d(GpG) and c) interstrand l,2d(GpG) platination by cisplatin. Diagrams from ref [ 48 ]
  • Figure 17 illustrates the cell viability plots for the A2780 cell line with cisplatin, [X16]CI and [X17JC1.
  • the Di- ⁇ - chloro(n 4 -l,5-cyclooctadiene)ruthemum(II) used was previously synthesised by the Lynam research group according to the literature procedure 53 . All chemicals used were purchased from Sigma-Aldrich UK, with the exception of cis-cis- ⁇ , 3,5- Cyclohexanetncaboxylic acid (TCI UK) and ruthenium trichloride hydrate (Precious Metals Online).
  • V P C 8.7 Hz, ?Ph 3 , Ar 3 ), 44.0 (s, CH, Cy 1 ), 43.8 (s, CH, Cy 2 ), 35.0 (s, CH 2 , Cy 3 ),
  • ATR-IR (cm 1 ) 3462, 3283, 3240, 3050, 2888, 1649, 1588, 1480, 1432 (P-Ph), 1367, 1346, 1270, 1211, 1183, 1156, 1089, 1027, 968, 905.
  • ATR-IR (cm-') 3281, 3237, 3137, 3049, 2896, 1590, 1480, 1434 (P-Ph), 1265, 1158, 1092, 1027, 03.
  • Trisacetoratrile-K 3 N ⁇ 5 -cyclopentadienylmtheruum(II) hexafluorophosphate (4 mg) and c/s-tach (2mg) were taken up in CD 2 CI2 (0.5 mL) and allowed to mix for 5 minutes. The solution was left to stand for 24 hours, over which crystals formed.
  • ATR-IR 3383, 3211, 3101, 2919, 1602, 1444, 1369, 1226, 1127, 1066, 1050, 1015, 910.
  • ESI-MS mJz 244.5570 ([Ru(dmso-S)(K 2 -phen)(K 3 -c/i-tach)] 2+ , Calcd 244.5565, 100%).
  • ATR-IR 3374, 3251, 4149, 2922, 1602, 1432, 1226, 1126, 1016, 912. Elemental Analysis
  • ATR-IR 3345, 3221, 3168, 3118, 2911, 2266 (ON), 1619, 1365, 1228, 1185, 1129, 1033, 916.
  • Integrations of the 1H NMR spectrum recorded in anhydrous CD2CI2 indicates at least 1 equivalent of water present.
  • the A549 cell line was kindly donated by The Technology Facility, Department of Chemistry, University of York.
  • the A2780 cell line was purchased from the ECACC.
  • Cell cultures were maintained in a 90% humidified atmosphere of C0 2 at 37 °C.
  • Cell cultures were maintained in DMEM (A549) or RPMI (A2780) supplemented with 2 mM glutamine and 10% Foetal Bovine Serum.
  • Sub-confluent cultures (70-80%) were split at a seeding of 1 :3 to 1 :6 using 0.25% Trypsin/EDTA.
  • Culture medium and FBS were obtained from Invitrogen Gibco and all other materials from Sigma.
  • Cells were seeded at a density of 1,000 cells per well (A549) or 2,500 cells per well (A2780) in 100 uL of their respective culture medium in a 96 well plate, with positive (columns 1 and 11) and negative (columns 2 and 12) controls located at each end of the plate. Positive controls consisted of culture medium with no cells, representative of 100 % inhibition of MTT metabolisation, and negative controls consisted of untreated cells, representative of 0 % inhibition. Cells were allowed to adhere to the plate surface for 24 hours during incubation before addition of drug. 100 of culture medium was added to each control well, and 100 uL of a 2x solution of the compound to be tested in culture medium to the remaining wells. A total of eight concentrations were tested, performed in octuplicate and typically between 300 uM and 0.1 ⁇ , with the eight concentrations selected to fall on the dose-response curve for the compound.
  • the cells were incubated with the drug for 72 hours before addition of 50 ⁇ , of MTT (2 mg mL) in PBS and incubation for a further 2 hours, over which the MTT was metabolized to insoluble formazan crystals.
  • the plates were centrifuged at 500g for 10 minutes and 220 uL of the culture medium in each well removed and the formazan solubilised by addition of 150 uL DMSO. The plate was shaken to ensure complete dissolution of the formazan, before absorbance at 540 run recorded using a Hidex Plate Chameleon V plate reader. The value for each concentration of drug was plotted graphically as a percentage of the negative control compared to the positive.
  • the data was fitted using a sigmoidal function and the concentration of drug to cause 50 % reduction of the absorbance compared to control values calculated as the IC50 value.
  • Statistical calculations were performed using Origin v8.5. Experiments were performed in triplicate, and the overall IC50 value calculated as the average of those obtained.
  • the cells Derived from a 58 year old Caucasian male.
  • the cells can synthesise lecithin utilising the cytidine diphosphocholine
  • Occasional cells may also contain inclusion bodies although they are not known to carry any human pathogen.
  • Subculture Routine at 2-4x10,000 cells/cm 2 using 0.25% trypsin or
  • trypsin EDTA 5% C02; 37°C.
  • FBS Bovine Serum
  • A2780 human ovarian cancer cell line was established from tumour tissue from an untreated patient. Cells grow as a monolayer and in suspension in spinner cultures.
  • A2780 is Cell Line Description: the parent line to the cisplatin resistant cell line A2780 cis
  • Tissue ovary
  • Subculture Routine at 3-6xlO,O0Ocells/cm 2 using 0.25% trypsin or
  • trypsin EDTA 5% C02; 37°C.

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Abstract

There is described a complex of formula I: in which, R1, R2, R3, R4, R5 and R6 are each, hydrogen, alkyl CI to 20 alkenyl CI to 20, aryl, alkyl(ci t0 20)aryl, alkenyl(Ci t0 20>aryl, heteroaryl, etc.; R7, R8 and R9 are each, hydrogen or alkyl CI to 20; L1, L2 and L3, are each a ligand; in free or in salt form.

Description

Synthesis and anticancer activity of ruthenium (11) cis-cis- 1,3,5- triaminocyclohexane complexes
Field of the Invention
The present invention relates to novel therapeutically active agents and to processes for the preparation thereof.
More particularly, the invention relates to novel ruthenium (Π) cis-cis- 1,3,5- triaminocyclohexane (tach) complexes and to their use and methods for treating proliferative pathologies, in particular cancers, and to methods for the preparation thereof.
Background to the Invention
Every year in the UK, nearly 300,000 new cases of cancer are diagnosed and an estimated 12.7 million worldwide, with deaths of 156,000 and 7.6 million respectively. These figures translate to one in three people in the UK developing a form of cancer at some point in their life, a diagnosis every two minutes, and one in every four UK deaths. [Cancer Res. UK] Cancer is a disease which is defined by two properties: uncontrollable growth, where cells divide beyond the normal restraints of a cell, and - when malignant - invasion into, and the destruction of either surrounding tissues or other locations in the body from via the lymph or blood. Most cancers are tumours (solid growths), however some cancers, such as leukaemia, are not. A single genetic mutation in the replication of a cell is insufficient to cause uncontrollable cancerous growth. A series of independent mutations must occur, all within the lineage of a single cell, and these mutations must overcome natural selection and cell control mechanisms, accounting for the low incidence of cancers compared to the number of expected mutations within a lifetime. Such a requirement for multiple mutations accounts for the increased incidence of cancer with age, where cells have undergone more cell divisions, and therefore a higher chance of mutation. Cancers are rarely diagnosed within the early stages of mutations, and are only detectable when they reach advanced stages, such as invasive carcinomas.
Since global approval in 1979, cisplatin II has become a significant tool in the treatment of lung, testicular, ovarian and bladder cancers as the only transition metal- based chemotherapeutic in clinical use for cancer treatment under the trade name of Platinol®. The potential of cisplatin as an anticancer agent after its initial discovery in 1845 was only realised by Rosenberg in 1965 when the serendipitous production of cisplatin at a platinum electrode inhibited the growth of E-coli bacteria. ' 1989 saw the global approval of carboplatin 12 for clinical use, under the name Paraplatin®, a modified cisplatin moiety with a bidentate dicarboxylate used in the treatment of ovarian, lung, head and neck cancers, designed specifically to reduce the side effects of cisplatin.3' 4 Sales of carboplatin surpassed those of cisplatin, with 2003 and 2004 sales reported as 905 and 673 billion dollars respectively.5 Only in 2002 was the last platinum drug approved globally, oxaloplatin 13 under the name Eloxatin® for use in colorectal cancer, as the first drug to overcome cisplatin cross resistance.6' 7
Figure imgf000004_0001
cisplatin carboplatin oxaloplatin
II 12 13
Figure 1: Structures of platinum based anticancer agents
Carboplatin 12 and oxaloplatin 13 are both aquation resistant due to the chelating ligand, and therefore undergo ligand exchange much more slowly than cisplatin II. This effect accounts for the greatly reduced general toxicity of these complexes and reduced side effects, from the reduced levels of active drug in the kidneys and gastrointestinal tract.3
Since the success of platinum in cancer chemotherapy, the search for other metallic complexes with cytotoxic behaviour began, for new compounds/ complexes with equal or greater activity and lower toxicity, combating the major problems with platinum. Platinum drugs are significantly associated with severe side effects, from the poor selectivity for cancer cells and toxicity to all cells - including healthy cells.8' 9 Platinum resistance, both primary and acquired, limits the use of these drugs.
At present, the most promising alternative for platinum as a cancer chemotherapy treatment which reduces the undesired properties of cisplatin based drugs is ruthenium.10"15 Ligand exchange kinetics for ruthenium complexes are similar to those observed with platinum in aqueous solution, occurring much more slowly when compared to other metal complexes, a key property in anticancer activity. Ruthenium is known to be systematically less toxic than platinum, possibly through ruthenium's ability to mimic iron in a biological environment,16 Cellular uptake of iron occurs through binding to serum transferrin and albumin proteins, which solubilise and transport the metal ions in plasma. Since cancer cells have a greater requirement for iron this results in up-regulation of the number of transferrin receptors on the cell surface and therefore greater uptake of iron-loaded transferrin. In vivo studies have shown that ruthenium concentration is 2 to 12 times greater in cancer cells than in healthy cells, dependent upon cell type. [Int. J. One. 2000, 17:353] Thus, ruthenium can be considered as more specific towards cancer cells than healthy cells and therefore less toxic towards healthy cells.
The first ruthenium compounds to be realized for their potential as anticancer agents were discovered in 1976 by Durig et al. when it was observed that the complex fac- Ru( H3)3Cl3 14 inhibited the growth of E. colt cells, at similar concentrations to those of cisplatin.17 Later, in 1980, Clarke et al. evaluated the cytotoxic properties of cis- Ru(NH3) Cl2 15, which also exhibited anticancer properties.18 While these complexes were active, poor water solubility prevented further investigation into their use as pharmaceuticals.19
Figure imgf000005_0001
Figure 2: Early ruthenium cliloro-ammine anticancer complexes
Since the initial discovery of the anticancer ruthenium chloro-ammine complexes, numerous ruthenium (Π) and (III) compounds were studied for their anticancer properties. One of the most well-known complexes is trans-RuC^dmso-S^, selected for improved water solubility over the ammine complexes.20 The tn s-complex is more cytotoxic than the cw-isomer, contrary to the findings of cisplatin studies, indicating an alternative mechanism of action between ruthenium (II) and platinum (II).
Currently, only two ruthenium complexes have successfully entered phase I clinical trials. The first progress was made by Keppler, with the imidazole and indole complexes [imiH]rr ra-[RuCl4(iV-imi)2] and [indH]rraw-[Ru(N-ind)2Cl4] (KP1019, 16) (imi = imidazole, ind = indole).12 In addition, Alessio and Sava reported the ruthenium imidazole-dimethylsulfoxide complex,
Figure imgf000006_0001
imi)] (NAMI-A, 17), which became the first ruthenium complex to enter clinical trials in 1999.12
Figure imgf000006_0002
KP1019 NAMI-A
16 17
Figure 3: NAMI-A and KP1019, the only two ruthenium complexes to reach clinical trials for use in anticancer therapy. At present NAMI-A is still in a phase Π study, and a phase Π study with KP1019 for use in patients with advanced colorectal cancer is being planned.
The ruthenium (HI) species described are relatively unreactive in the +3 oxidation state in normal, oxidizing tissue. It is only when reduction occurs to ruthenium (Π) in hypoxic conditions found in tumours, as explained by Clarke in the "activation by reduction" theory, that the complexes become biologically active.21 Therefore, it is believed that the ruthenium (ΠΙ) complexes are pro-drugs to the active ruthenium (II) species. Studies show that NAMI-A, reduced by ascorbic acid to ΝΑΜΙ-ΑΛ, prior to administration proved to be significantly more efficient than the parent complex, which is in accordance with Clarke's theory.22
The area of ruthenium (Π) complexes containing an ? 6-arene ligand as anticancer agents was pioneered simultaneously by Dyson and Sadler in 2001, with initial prototypes of RuCl2(p-cymene)(PTA) (PTA = P-l,3,5-triaza-7-phosphatricyclo- [3.3.1.1]decanephosphine) 18, termed "RAPTA-C" and [RuCl(bip)(en)]PF6 19 (bip = biphenyl) respectively.23, 24 Like NAMI-A, RAPTA-C is an antimetastatic agent, inhibiting lung metastases, despite low activity in vitro. Sadler's [RuCl(bip)(en)]PF6 is cytotoxic in vitro and in vivo, like KP1019 and cisplatin, with very high activity.
Figure imgf000008_0001
Figure 4: RAPTA-C (Dyson) and [RuCI(p-cym)(en)]PF6 (en = 1,2-ethylenediamine) (Sadler), two early prototype ruthenium arene anticancer complexes.
A series of novel r -are ruthenium (Π) diamine complexes was reported in 2001 by Sadler and co workers, of the type [Ru(X)( 6-arene)(YZ)] +, where YZ is a bidentate ligand (Ν,Ν-, Ν,Ο- or 0,0-), and X is a good leaving group.24
Figure imgf000008_0002
Figure 5: General Scheme of Sadler's Complexes. X = good leaving group, YZ :
bidentate ligand.
The lead complex from the initial report, consisting of biphenyl as the >76-arene, ethylenediamine as the chelating ligand and chloride as the leaving group, 19, was found to be equipotent to carboplatin in A2780 human ovarian cancer cells. The p- cymene analogue 110 was also equipotent with carboplatin. Employment of un- substituted benzene in 111 further reduced activity. It was later reported that use of highly extended aromatics, such as tetrahydroanthrocene in 112 exhibited greater activity than 19, equipotent to cisplatin. The complexes do not inhibit topoisomerase enzymes which are involved in DNA replication; however they do form strong interactions with the guanine base in DNA, providing the drug directly targets DNA, in a similar way to cisplatin.25'26
Figure imgf000009_0001
11 cisplatin 0.6 10 8.0
12 carboplatin 6 10
Table 1: Prototype ruthenium ethylenediamine complexes by Sadler and coworkers, with IC50 values for A2780 and cross resistance profiles, compared to cisplatin and carboplatin.
The cross resistance of these complexes with the cisplatin-resistant cell line, A2780cis and multi-drug resistant cell line, A2780AD was determined.25 Complexes 19 and 112 both retained activity in A2780cis, however activity was lost in the multi-drug resistant cell line. Therefore, it was concluded that the ruthenium (Π) ethylenediamine complexes have a different mechanism of DNA damage compared to cisplatin.
Upon dissolution in water, the ruthenium-chloride bond in 19 readily aquates to form aqua adducts, where chloride is exchanged for ΟΗ2/ΟΗ', at rates greater than twenty times that of cisplatin. Anation also occurs at comparatively rapid rates in 100 mM NaCl solution to reform the chloride complex.28 Once ruthenium ^6-arene complexes reach the nucleus and interact directly with DNA, there is strong preference in binding to the N7 of guanine, verified by interactions of [RuCl(bip)(en)]PF6 19 with an oligonucleotide and analysis by negative ion ESI-MS.24 DNA ruthenation is similar to that of platination by cisplatin, and correlates to cytotoxic potency.29
Unlike cisplatin drugs, 19 binds to a single guanine-N7 residue, and forms a stabilised complex through a hydrogen bond between the ethylenediamine N-H and the guanine- 06, possibly accounting for the unique cross resistance profile and a different method of inhibiting cell replication once bound to DNA.26
Structure-Activity relationships were conducted in 2006 by Sadler et al. to determine the effect of the arene and chelating ligand on activity in A2780 human ovarian cancer cells.27 As expected from previous work, extended aromatic systems gave the best activity, such as QPhs 114, flu 115 and dhp 116, due to the increased lipophilicity of the complex relating to a greater ability to pass through cell membranes. Addition of polar substituents to the arene ligand, such as -CH2OH 117, -C02Me 118 or - CONH2 119, resulted in reduced activity in comparison.
Figure imgf000010_0001
Table 2: Effect on IC50 values for the A2780 cell line with structural alterations of the arene ligand. Extension of the aromatic system to terphenyls once again supported the hypothesis with improved activity, attributed to greater Iipophilicity and stronger intercalation interactions with DNA. The /tora-terphenyl complex 120 exhibited cytotoxicities comparable to cisplatin, whereas the ortho- 121 and meta- 122 variants, without the ability to extend and intercalate with DNA, lost activity in comparison. Once again, the complexes were not cross resistant with cisplatin, supporting an alternative mechanism.30
Figure imgf000011_0001
11 cisplatin 0.9 8 2.8 18.6
Table 3: Cytotoxic activity for complexes containing terphenyl ligands, with ICso values for the A2780, CHI ovarian carcinoma and SKBR3 mammary carcinoma cell lines.
Variation of the ethylenediamine ligand by addition of groups to the alkyl backbone resulted in little effect on the activity, however removal of some or all amine protons, in the case of iV,N,iV',N'-tetramethylethylenediamine (tmeda) and 2,2'-bipyridyl derivatives, resulted in loss of activity.
N,0- chelating ligands, such as amino acids and 8-hydroxyquinoline, possessed no activity towards A2780 (IC5o > 100 μΜ in all cases), thought to be due to deactivation under biological conditions despite demonstrating fast aquation kinetics and strong binding to 9-ethylguanine.27 Ruthenium (Π) arene complexes, containing f-l,3,5-triaza-7-phosphatricyclo- [3.3.1.1]decanephosphine (PTA), termed 'RAPTA' were initially reported in 2001. The ara-cymene derivative, RuCl2(p-cym)(PTA) "RAPTA-C" 18 exhibited pH dependant DNA damage, with the pH with the greatest amount of damage correlating to that of cancer cells.23 It was not until 2005, that the in vitro and in vivo activity of several variants of the arene ligand within the RAPTA family was evaluated.
In vitro biological cytotoxic studies with TS/A mouse adenocarcinoma cancer and HBL-100 human mammary (non-tumour) cell lines revealed that these complexes are active against the cancer cell line, however inactive in comparison with non-tumour cells, up to 300 μΜ. N-methylation of the PTA ligand in 123 and 18 resulted in loss of selectivity to the cancer cells with I23n and I8n. On the basis of similarities to NAMI- A with respect to in vitro studies, both 18 and 123 were selected for in vivo evaluation on CBA mice bearing the MCa mammary carcinoma. Although reduction of growth of the primary tumour was not observed, activity was seen against lung metastases, similar to the case of NAMI-A, thus the RAPTA series of complexes act as antimetastatic complexes. While 18 has lower activity in comparison to NAMI-A, the superior clearance rates enabled the RAPTA series to be a viable contender for consideration for further studies.31
Figure imgf000013_0001
Scheme 1: Aquation of RAPTA-C 18 in low chloride concentrations
Aquation and hydrolysis of RAPTA-C, determined by UV/Visible and NMR spectroscopy revealed the important steps in activation of the complexes in biological systems. The major product was found to be [RuCl(p-cymene)(OH2)(PTA)]+, along with [Ru(OH)(p-cymene)(OH2)(PTA)]+ as the minor product, with the originating dichloro species also present. Aquation is approximately three times faster than for [RuCl(bip)(en)]PF6 19 and related complexes and two orders of magnitude faster than cisplatin. While the fully aquated hydroxy complex is less reactive towards biomolecules than the chloride-aqua species, the relatively high pKa values of these complexes mean only small amounts are present, unlike cisplatin, where the unreactive hydroxy species predominates. Aquation of RAPTA-C is suppressed under physiological chloride concentrations of blood (100 mM), but upon entering the cell, where the chloride concentration is 4 mM, aquation occurs to yield the active species.32
Figure imgf000014_0001
Carbo-RAPTA Oxalo-RAPTA
126 127
Figure 7: RAPT A analogues of carboplatin and oxaloplatin
ESI-MS investigations into the binding complexes RAPTA-C, carbo-RAPTA 126 and oxalo-RAPTA 127 (RAPTA analogues of the platinum complexes currently in world- wide clinical use, which are designed to resist hydrolysis) with the small proteins horse heart cytochrome c (cyt c) and egg white lysozyme revealed the ability to bind to these proteins, with a preferential binding site of surface histidines.33
The requirement for the aromatic fragment in ruthenium (Π) anticancer complexes was examined by Alessio et al. through replacement with the cyclothioether, 1,4,7- trithiacyclononane ([9]aneS3). Complexes based on those from both Dyson and Sadler's libraries were synthesized and tested for biological activity.
201
Figure imgf000015_0001
130
Figure 8: [9]aneS3 analogues of ruthenium arene complexes which show anticancer activity.
In vitro tests were performed with mouse adenocarcinoma cancer cell line (TS/A) and human mammary normal cell line (HBL-100). The results revealed that the [9]aneS¾ complexes are comparable to the arene analogues, with minimal loss of activity and retained selectivity for the tumour cells over health cells. As expected, the most cytotoxic complex was the ethylenediamine derivative, 130, as is with the case of the organometallic variant. 3
Further studies were continued with the [9]aneS ligand, through the use of bipyridyl ligands with functional groups capable of hydrogen bond interactions with relevant biomolecules. However, none was found to be of sufficient cytotoxicity in vitro against the breast carcinoma MDA-MB-231 or oral carcinoma KB cell line. The results from the investigation corresponded with those of Sadler's structure-activity relations, where the introduction of other N-N chelates dramatically reduces the biological activity of the complex.35
Figure imgf000016_0001
Figure 9: Structure and biological evaluation of ruthenium Tpm complexes
Clucas, W. A. et al, Inorg. Chem. 1996 35 p6789 reported a ruthenium triazacyclononane (tacn) complex. Das, S et al, J Inorg. Biochem. 2010 103 p93 reported half-sandwich ruthenium arene complexes with chelating phosphines as anticancer agents. Although not reported, it would be expected that the half-sandwich ruthenium arene complexes have poor aqueous solubility. International Patent application No. WO 01/10870 (Brechbiel & Planalp) describes transition metal complexes of Ν,Ν',Ν''-trialkyl- cis,cis-l,3,5-triaminocyclohexanes. However, WO 0'870 focuses on the delivery of copper complexes for imaging agents and does describes complexes for use as therapeutic agents. International Patent application No. WO 2006/016069 (Pfeffer) describes ruthenium complexes for treating cancers. However, the complexes described in WO Ό69 suffer from poor water solubility and are generally associated with therapeutically unacceptable anions, such as, hexafluorophosphate. Whilst hexafluorophosphate salts are often advantageous as an inert and non-coordinating counter ion in solvolysis, the anion is slow to hydrolyse and is unsuitable for use in a therapeutically active agent. WO '069 does not disclose cis-cis- 1,3,5-triaminocyclohexane complexes.
International Patent application No. WO 2011/001109 (Pfeffer) also describes ruthenium complexes for treating cancers, but again the complexes described are generally associated with the therapeutically unsuitable hexafluorophosphate anion and the complexes suffer from poor water solubility. WO '109 does not disclose cis- cis- 1,3,5-triaminocyclohexane complexes. Therefore, there is a need for novel anticancer agents which could be an alternative to those currently used and/or which would have minimal undesirable side effects and/or improved aqueous solubility.
Summary to the Invention
The cis-cis- 1,3,5-triaminocyclohexane ligand, cw-tach, has been widely used with first row transition metals in complex design, for many applications.
Figure imgf000018_0001
Figure 10: cis-cts-l,3,5-triaminocyclohexane (crs-tach). When bound to a metal centre, the amino groups adopt an axial conformation.
The ligand, which when bound to a metal centre forms an adamantine-like structure, has applications include use as a building block in coordination clusters,36 RNA and DNA cleavage,37"39 catalysis,40 radiopharmaceuticals, 1, 2 anticancer agents,43"45 and the mimicking of transition metal biomolecules for their study.46'47
Much of the past and current research of cw-tach has been based around first row transition metal bioinorganic chemistry. Complexation with ruthenium (Π) has at present been unreported in the literature.
Through the use of cw-tach and other similar ligands, the problem of water solubility can be overcome, while also exhibiting distinctly different properties on the complex.
As cw-tach is a /ac-coordinating ligand, it can therefore be compared to the half sandwich complexes reported by Dyson and Sadler. The cyclohexane ring in m-tach may act as a hydrophobic face to the complex, whereas the amine groups will serve to produce a hydrophilic metal centre, and aid water solubility through hydrogen bonds.
Figure imgf000019_0001
Figure 11: General structure of ruthenium (II) cis-tach complexes with chloride leaving group and a chelating ligand. Charges are omitted for clarity.
Ruthenium (Π) cis-tach complexes, with a chloride ligand, will be structurally similar to cisplatin, however more closely related to oxaloplatin with the bidentate trans-1,2- diaminocyclohexane. Therefore, the cis-tach complexes may be closer in their chemistry to the proven cisplatin complexes, and possess greater activity.
The amine groups of cis-tach also resemble those in Sadler's half-sandwich ethylenediamine complexes, where an amine ligand is adjacent to the chloride ligand, and ultimately, the DNA upon coordination. The functionality of this important ligand is incorporated into the^ac-coordinating ligand, leaving two vacant coordination sites, occupied by a chelating ligand, for example. This chelating ligand can be altered to infer different electronic properties onto the metal, additional hydrophobic groups to change lipophilicity, or by addition of groups to aid water solubility.
The present invention proposes ruthenium complexes which have, inter alia, beneficial antitumour properties and/or improved aqueous solubility over known prior ruthenium or platinum therapeutic agents. Therefore, according to a first aspect of the invention there is provided a complex of formula I:
Figure imgf000020_0001
in which,
R1, R2, R3, R4, R5 and R6, which may be the same or different are each, hydrogen or alkyl CI to 20, alkenyl CI to 20, aryl, alkyl(Cj (0 20)aryl, alkenyl(Ci to 20)aryl, heteroaryl, a sugar, an amino acid, a nucleoside, a nucleotide or a peptide;
R7, R8 and R9, which may be the same or different are each, hydrogen or alkyl CI to
20;
L1, L2 and L3, which may be the same or different, are each selected from the group comprising halogen (halogen may optionally be a bridging moiety between two groups of formula I), -PR10RUR12, -NCR13, -S(0)R14R15; or
a pair of any two of L1, L2 and L3 may comprise a moiety -R16R17N-(CHR18)n-
NR19R20 or -R2,R22P-(CHR23)m-PR R25;
a pair of any two of L1, L2 and L3 may comprise a moiety of formula VI;
Figure imgf000020_0002
a pair of any two of L1, L2 and L3 may comprise a C6 to 20 cycloalkyldiene; L1, L2 and L3 may together form a 6- to 8- membered arene;
n and m, which may be the same or different, are each an integer 1 to 6
R10. R11 and R12, which may be the same or different, are each alkyl CI to 20 or aryl optionally substituted by one or more alkyl CI to 20;
R13, R14 and R15 which may be the same or different, are each alkyl CI to 20 or aryl optionally substituted by one or more alkyl CI to 20;
R16, R17, R18, R19, R20, R21, R22, R23, R24 and R25, which may be the same or different, are each alkyl CI to 20 or aryl optionally substituted by one or more alkyl CI to 20; any adjacent pair of R18 or R23 may together form a bond;
R26 and R27, which may be the same or different, are each hydrogen, alkyl CI to 20 or R26 and R27 together form an optionally aromatic ring;
and isomers thereof;
in free or in salt form. The valency of the complex of formula I may vary depending upon the nature of the ligands and may be +1 or +2 (charges are omitted for clarity). Consequently, in the salt form of the complex of formula I the counter ion may be a monovalent anion or a bivalent anion or more than one monovalent anion may be present. A preferred group of complexes which may be mentioned is the group of complexes of formula I in which R1, R2, R3, R4, R5 and R6, which may be the same or different, are each, hydrogen or alkyl CI to 20, alkenyl CI to 20, aryl, alkyl(Ci t0 20)aryl, alkenyl(C1 to 20>aryl or heteroaryl. A preferred group of complexes which may be mentioned is the group of complexes of
1 2 3 10 17 18 formula I in which a pair of L , L and L , represent a moiety -R R N-(CHR )„- NR19R20 or -R2,R22P-(CHR23)m-PR24R23;
and R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, m and n, are each as hereinbefore defined.
R18 and 23 are each preferably hydrogen.
A further preferred group of complexes which may be mentioned is the group of complexes of formula I in which a pair of Ll, L2 and L3, represent a moiety -R21R22P- (CHR23)m-PR24R25,
and R2,, R22, R2\ R 4, R25 and m are each as hereinbefore defined. Preferably R23 is hydrogen.
Preferably R21, R22, R24 and R25 are each aryl, e.g. phenyl. Preferably m is an integer from 1 to 4. Preferably R1, R3 and R5 are each hydrogen.
Preferably R1, R2, R3, R4, R5 and R6 are each hydrogen. Preferably R7, R8 and R9 are each hydrogen. When a pair of L1, L2 and L3, represent a moiety of formula VI, R26 and R27 are preferably the same and may each be hydrogen, to provide a ligand of formula Via, or R26 and R27 together form an aromatic ring, to provide a ligand of formula Vlb:
Figure imgf000023_0001
When a pair of L1, L2 and L3, represent a C6 to 20 cycloalkyldiene a preferred moiety is a cyclooctadiene, e.g. T|4-l,5-cyclooctadiene.
According to a further aspect of the invention there is provided a complex of formula I as hereinbefore defined in which L1, L2 and L3, which may be the same or different, are each selected from the group comprising halogen (halogen may optionally be a bridging moiety between two groups of formula I), -PR'°R"R12, -NCR13; or
a pair of any two of L1, L2 and L3 may comprise a moiety -R16RI7N-(CHRI8)n-
NR19R20 or -R21R22P-(CHR23)M-PR24R25;
a pair of any two of Ll, L2 and L3 may comprise a moiety of formula VI;
Figure imgf000023_0002
a pair of any two of L1, L2 and L3 may comprise a C6 to 20 cycloalkyldiene L1, L2 and L3 may together form a 6- to 8- membered arene. According to a further aspect of the invention there is provided a complex of formula I as hereinbefore defined in which L , L and L are each as hereinbefore defined provided that not more than one of L1, L2 and L3 is -PR10RnR12.
As used herein, the term "alkyl" refers to a fully saturated, branched or unbranched hydrocarbon moiety, i.e. primary, secondary or tertiary alkyl or, where appropriate, cycloalkyl or alkyl substituted by cycloalkyl, they may also be saturated or unsaturated alkyl groups. Where not otherwise identified, preferably the alkyl comprises 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, 1 to 10 carbon atoms, 1 to 7 carbon atoms, or 1 to 4 carbon atoms. Representative examples of alkyl include, but are not limited to, methyl, ethyl, «-propyl, iro-propyl, «-butyl, sec-butyl, wo-butyl, ferf-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl, 2,2- dimethylpentyl, 2,3-dimethylpentyl, #-heptyl, «-octyl, n-nonyl, rc-decyl and the like.
As used herein, the term "cycloalkyl" refers to saturated or unsaturated monocyclic, bicyclic or tricyclic hydrocarbon groups of 3-12 carbon atoms, preferably 3-9, or 3-7 carbon atoms, each of which can be optionally substituted by one, or two, or three, or more substiruents, such as alkyl, halo, oxo, hydroxy, alkoxy, alkyl-C(O)-, acylamino, carbamoyl, alkyl-NH--, (alkyl^N--, thiol, alkyl-S--, nitro, cyano, carboxy, alkyl-O- C(0)-, sulfonyl, sulfonamide, sulfamoyl, heterocyclyl and the like. Exemplary monocyclic hydrocarbon groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl and cyclohexenyl and the like. Exemplary bicyclic hydrocarbon groups include bornyl, indyl, hexahydroindyl, tetrahydronaphthyl, decahydronaphthyl, bicyclo[2.1.1]hexyl, bicyclo[2.2.1]heptyl, bicyclo[2.2. ljheptenyl, 6,6-dimethylbicyclo[3.1.1 Jheptyl, 2,6,6-trimethyl bicyclo[3.1.1]heptyl, bicyclo[2.2.2]octyl and the like. Exemplary tricyclic hydrocarbon groups include adamantyl and the like. As used herein, the term "aryl" refers to an aromatic carbocyclic ring system containing 6 to 14 ring carbon atoms, which may be unsubstituted or substituted as defined. A preferred aryl moiety is phenyl, i.e. unsubstituted phenyl.
As used herein, the term "heteroaryl" refers to a 5-14 membered monocyclic- or bicyclic- or polycyclic-aromatic ring system, having 1 to 8 heteroatoms selected from N, 0 or S. Preferably, the heteroaryl is a 5-10 or 5-7 membered ring system. Typical heteroaryl groups include 2- or 3-thienyl, 2- or 3-furyl, 2- or 3-pyrrolyl, 2-, 4-, or 5- imidazolyl, 3-, 4-, or 5- pyrazolyl, 2-, 4-, or 5-thiazolyl, 3-, 4-, or 5-isothiazolyl, 2-, 4-, or 5-oxazolyl, 3-, 4-, or 5-isoxazolyl, 3- or 5-1,2,4-triazolyl, 4- or 5-1,2, 3-triazolyl, tetrazolyl, 2-, 3-, or 4-pyridyl, 3- or 4-pyridazinyl, 3-, 4-, or 5-pyrazinyl, 2-pyrazinyl, 2-, 4-, or 5-pyrimidinyl.
The term "heteroaryl" also refers to a group in which a heteroaromatic ring is fused to one or more aryl, cycloaliphatic, or heterocyclyl rings, where the radical or point of attachment is on the heteroaromatic ring. Non-limiting examples include but are not limited to 1-, 2-, 3-, 5-, 6-, 7-, or 8- indolizinyl, 1-, 3-, 4-, 5-, 6-, or 7-isoindolyl, 2-, 3-, 4-, 5-, 6-, or 7-indolyl, 2-, 3-, 4-, 5-, 6-, or 7-indazolyl, 2-, 4-, 5-, 6-, 7-, or 8- purinyl, 1-, 2-, 3-, 4-, 6-, 7-, 8-, or 9-quinolizinyl, 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolinyl, 1-, 3-, 4- , 5-, 6-, 7-, or 8-isoquinolinyl, 1-, 4-, 5-, 6-, 7-, or 8-phthalazinyl, 2-, 3-, 4-, 5-, or 6- naphthyridinyl, 2-, 3- , 5-, 6-, 7-, or 8-quinazolinyl, 3-, 4-, 5-, 6-, 7-, or 8-cinnolinyl, 2-, 4-, 6-, or 7-pteridinyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, or 8-4aH carbazolyl, 1-, 2-, 3-, 4-, 5-,
6- , 7-, or 8-carbazolyl, 1-, 3-, 4-, 5-, 6-, 7-, 8-, or 9-carbolinyl, 1-, 2-, 3-, 4-, 6-, 7-, 8-, 9-, or 10-phenanthridinyl, 1- , 2-, 3-, 4-, 5-, 6-, 7-, 8-, or 9-acridinyl, 1-, 2-, 4-, 5-, 6-,
7- , 8-, or 9-perimidinyl, 2-, 3-, 4-, 5-, 6-, 8-, 9-, or 10-phenathrolinyl, 1-, 2- , 3-, 4-, 6-, 7-, 8-, or 9-phenazinyl, 1-, 2-, 3-, 4-, 6-, 7-, 8-, 9-, or 10-phenothiazinyl, 1-, 2-, 3-, 4-,
6- , 7-, 8-, 9-, or 10-phenoxazinyl, 2-, 3-, 4-, 5-, 6-, or 1-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, or 10- benzisoqinolinyl, 2-, 3-, 4-, or thieno[2,3-b]iuranyl, 2-, 3-, 5-, 6-, 7-, 8-, 9-, 10 or 1 l-7H-pyrazino[2,3-c]carbazolyl,2-, 3-, 5-, 6-, or 7-2H- furo[3,2-b]-pyranyl, 2-, 3-, 4- 5-, 7-, or 8-5H-pyrido[2,3-d]-o-oxazinyl, 1-, 3-, or 5-lH-pyrazolo[4,3-d]-oxazolyl, 2-, 4-, or 54H-imidazo[4,5-d] thiazolyl, 3-, 5-, or 8-pyrazino[2,3-d3pyridazinyl, 2-, 3-, 5-, or 6- imidazo[2,l-b] thiazolyl, 1-, 3-, 6-, 7-, 8-, or 9-furo[3,4-c]cinnolinyl, 1-, 2-, 3-, 4-, 5-, 6-, 8-, 9-, 10, or l l-4H-pyndo[2,3-c]carbazolyl, 2-, 3-, 6-, or 7-imidazo[l,2- b][l,2,4]triazinyl3 7-benzo[b]thienyl, 2-, 4-, 5- , 6-, or 7-benzoxazolyl, 2-, 4-, 5-, 6-, or
7- benzimidazolyl, 2-, 4-, 4-, 5-, 6-, or 7-benzothiazolyl, 1-, 2-, 4-, 5-, 6-, 7-, 8-, or 9- benzoxapinyl, 2-, 4-, 5-, 6-, 7-, or 8-benzoxazinyl, 1-, 2-, 3-, 5-, 6-, 7-, 8-, 9-, 10-, or tl-lH-pyrroio[l,2-b3[2]benzazapinyl. Typical fused heteroaryl groups include, but are not limited to 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolinyl, 1-, 3-, 4-, 5-, 6-, 7-, or 8- isoquinolinyl, 2-, 3-, 4-, 5-, 6-, or 7-indolyl, 2-, 3-, 4-, 5-, 6-, 7-benzofuranyl, 2-, 4-, 5- , 6-,or 7-benzo[bJthienyl, 2-, 4-, 5- , 6-, or 7-benzoxazolyl, 2-, 4-, 5-, 6-, or 7- benzimidazolyl, 2-, 4-, 5-, 6-, or 7-benzothiazolyl.
A heteroaryl group may be mono-, bi-, tri- or polycyclic, preferably mono-, bi-, or tricyclic, more preferably mono- or bicyclic.
As used herein, the term "halogen" or "halo" refers to fhioro, chloro, bromo, and iodo. The term "sugar" may mean a natural or a synthetic sugar. Sugars that may be mentioned include, but shall not be limited to, glucose, glucosamine, glucuronic acid, ribose, and 2-deoxy derivatives thereof, e.g. 2-deoxy glucose, 2-deoxy-2-fluoro glucose and 2-deoxy ribose; and derivatives thereof.
The term "amino acid" used herein include, but shall not be limited to, alanine, arginine, asparagines, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, ornithine, phenylalanine, proline, selenocysteine, serine, taurine, threonine, tryptophan, tyrosine and valine; and derivatives thereof.
The term "amino acid" or "amino acids" refers to a naturally occurring a-amino acid and their stereoisomers, as well as non-natural amino acids such as amino acid analogues, synthetic amino acids, β-amino acids, γ-amino acids, N-methyl amino acids, and N-substituted glycines, in either the L- or D-configuration that function in a manner similar to the naturally occurring amino acids. "Stereoisomers" of naturally occurring amino acids refers to mirror image isomers of the naturally occurring amino acids, such as D-amino acids. "Amino acid analogues" refers to compounds that have the same basic chemical structure as naturally occurring amino acids, e.g. homoserine, norleucine, methionine sulphoxide, methionine methyl sulphonium and the like. In β- amino acids, the amino group is bonded to the β-carbon atom of the carboxyl group such that there are two carbon atoms between the amino and carboxyl groups. In γ~ amino acids, the amino group is bonded to the γ-carbon atom of the carboxyl group such that there are three carbon atoms between the amino and carboxyl groups. The term "peptide" or "peptides" refers to a compound made up of a single chain of D- or L-amino acids or a mixture of D- and L-amino acids joined by peptide bonds. Generally, peptides are from about 2 to about 50 amino acids in length. The peptides of the present invention may be preferably from about 2 to about 25 amino acids, more preferably from about 2 to about 10 amino acids, and most preferably from about 2 to 8 amino acids in length. The free amino-terminus and/or carboxyl-terminus on the peptides may optionally be protected by an amide, an alkyl, e.g. methyl, ester, a succinyl, or an acetyl group. Further chemical modifications may also be contemplated.
The term "nucleoside" shall include, but shall not be limited to, naturally occurring nucleosides, such as, adenosine, guanosine, cytidine, thymidine, and uridine; and modifications thereof. Modifications shall include, but shall not be limited to, those providing chemical groups that incorporate additional charge, polarisability, hydrogen bonding, and electrostatic interaction to the nucleosides. The term "nucleosides" may also include non-natural bases, such as, nitroindole, 5-aza-cytidine, 5-aza-2'- deoxycytidine, and dihydro-5-aza-2'-deoxycytidine; and modifications thereof. The term "nucleotides" shall mean are phosphate esters of nucleosides as hereinbefore defined. Thus, many of the chemical reactions which are utilised for nucleosides can also be utilised for nucleotides. It will be understood by the person skilled in the art that the aforementioned sugars, amino acids, peptides, nucleosides and/or nucleotides may be coordinated to a ruthenium moiety via one or more of nitrogen or a carboxying group. Specific complexes of formula I which may be mentioned include:
chloro(c is-cis- 1 ,3,5-triaminocyclohexane-K3N,N ', N ' ')bis(triphenylphosphane) ruthenium(II) hexafluorophosphate;
dichloro(cw^-l,3,5-triarmnocyclohexane-K3N,N',N' ')triphenylphosphane ruthenium(II)— dichloromethane;
-chloro-dicMoro-lκ1 ,2 1 -|l·is(cw-cώ-l,3,5-triaminoc clohexane)-
Figure imgf000029_0001
tetraphenylborate— dichloromethane;
acetonitrilechloro(c/s-c/s- 1 ,3,5-triammocyclohexane-K3N,N',N' ') triphenylphosphane ruthenium(rt) hexafluorophosphate;
bisacetonitrile(c s-cw- 1 ,3,5-triaminocyclohexane-K3JV;N',N' ') triphenylphosphane ruthenium(II) hexafluorophosphate,
chlorodimethylsulfoxide-KS-(c«-cw-l,3,5-rriarmnocyclohexane-K3N,N',N' ')
triphenylphosphane ruthenium(II) chloride— hydrate;
n5-cyclopentadienyl(m-c«- 1 ,3,5-triaminocyclohexane-K3N,N N ' ')ruthenium(H) hexafluorophosphate;
chlorobis(dimethylsulfoxide-K^(m-m^
ruthenium(II) chloride;
chloro(r|4- 1 ,5 -cyclooctadiene)(cw-cw- 1 ,3 ,5-triaminocyclohexane-K3N, Ν',Ν")
ruthenium(II) hexafluorophosphate; 2,2 '-bipyridine-K2N,N '-dimethylsulfoxide-KS-(cw-c/,s- 1 ,3 ,5-triaminocyclohexane- K N,N',N") ruthenium(II) chloride;
dimethylsulfoxide-KS-l,10-phenanthroline-K¼N'-(cis-ci5-l,3,5-triamino
cyclohexane-^N.N'.N' ')ruthenium(II) chloride;
dimethylsulfoxide-KS-l,2-diaminoethane-K^
K3N,N',N' ') ruthenium(H) chloride;
trisacetomtrile(c/s-cis-l,3,5-triaminocyclohexa^^ chloride; chloro [methylenebis (diphenylphosphane-K2P, ')]
Figure imgf000030_0001
cyclohexane-K3N,N',N' ')ruthenium(II) chloride— hydrate;
chloro [ethane- 1,2-diylbis (diphenylphosphane- 2 , ')] (cw,cw-l,3,5-triamino cyclohexane-K3N,N',N' ')ruthenium(II) chloride— hydrate;
chloro [propane- 1, 2 -diylbis(diphenyIphosphane-K2jP,/J ')] (CM CM- 1,3 ,5-triamino cyclohexane-K3N,N',N")ruthenium(II) chloride— hydrate;
chloro [butane- 1 ^-diylbis^iphenylphosphane-K2/*,/3 ')] (cis, cis- 1 ,3 ,5-triamino cyclohexane- 3jV,N',iV' ')ruthenium(II) chloride— hydrate,
chloro [(Z)-ethylene- 1 ,2-bis(diphenylphosphane-K2 ,^ ')] (cis> cis- 1 ,3 ,5-triamino cyclohexane-K3N,N',iV' ')ruthenium(II) chloride— hydrate;
chloro [phenylene-l,2-bis(diphenylphosphane-K2f ,P ')] (cw.cw-l^^-triamino cycIohexane-K3N,N',N' ')ruthenium(H) chloride— hydrate;
aquofethane-l^-diylbisCdiphenylphosphane-K2?, 5 ')] (c/s,cw-l,3,5-triamino cyclohexane-K3N,N',N' ')ruthenium(ll) bistrifluoromethane sulphonate; and aquo[propane- 1 ,3-diylbis(diphenylphosphane-K2 ,P ')](cis, cis- 1 ,3,5-triamino
cyclohexane-K3N,N',N' ')ruthenium(II) bistrifluoromethane sulphonate;
and isomers thereof;
in free or in salt form. A preferred group of complexes of formula I which may be mentioned include:
dichloroicw-cw-l^^-triaminocyclohexatie-KS N^N^jtriphenylphosphane ruthenium(n)— dichloromethane;
hloro-dichIoro-lκ1C ,2κ1 /-[bis(ci5-£^ 5-l,3,5-ίriam^noc clohe ane)- acetonitrilecWoroCcM-cw-l^^-triaminocyclohexane-K^N^N' ') triphenylphosphane ruthenium(II) hexafluorophosphate;
bisacetonitrile(cw-c/'s-l ,3,5-triaminocyclohexane-K3N,N',jV' ') triphenylphosphane ruthenium(II) hexafluorophosphate,
^-cyclopentadienyl(cw-cM ,3,5-rriaminocyclohexane- 3N,N N' ')mthemum(II) hexafluorophosphate;
chloro^ -l,5-cyclooctadiene)(c/s-c/i- 1 ,3,5-triarrtinocyclohexane-K3N,N',N' ') ruthenium(n) hexafluorophosphate;
trisacetonitrile(ci5-cw- 1 ,3,5-triaminocyclohexane~K3N,N',N' ')ruthenium(II) chloride; chloro [methylenebis (diphenylphosphane-K2P,P ')]
Figure imgf000031_0001
cyclohexane-K3N,N',N' ')mthedum(H) chloride— hydrate;
chloro [ethane- 1,2-diylbis (diphenylphosphane-K2P,P *)] (cjs,cis-l,3,5-rriamino cyclohexane-x3N;N',N' ')ruthenium(H) chloride— hydrate;
chloro [propane- l,2-diylbis(diphenylphosphane-K2P,P ')] (cw,m-l,3,5-triamino cyclohexane-K3N, JV ',Ν ' ')ruthenium(II) chloride— hydrate;
chloro [butane- 1 ,2-diylbis(diphenylphosphane-K2P, ')] (cis, cis- 1 ,3,5-triamino cyclohexane-K3N,N',N")ruthenium(n) chloride— hydrate;
chloro [(Z)-ethylene-l,2-bis(diphenylphosphane-K2P, ')] (cw, CM-l,3,5-triamino cyclohexane-K3N,N',iV")ruthenium(II) chloride— hydrate; and chloro [phenylene-l,2-bis(diphenylphosphane- P,P ')] (<?w,c«-l,3,5-triamino cyclohexane-K3N,N',N' ')ruihenium(II) chloride— hydrate;
and isomers thereof;
in free or in salt form.
According to a further aspect of the invention there is provided a complex of formula I as hereinbefore described as a medicament.
More particularly, there is provided a complex of formula I as hereinbefore described as a medicament for the treatment of a proliferative disorder.
The complexes of the invention are advantageous in the treatment or alleviation of disorders linked to cell hyperproliferation, in particular cancers, e.g. apoptosis of cancer cells. These cancers include those with solid or liquid tumours. Although a variety of cancers may be mentioned which include, but shall not be limited to one or more of primary cancer, breast cancer, colon cancer, prostate cancer, non-small cell lung cancer, glioblastoma, lymphoma, mesothelioma, liver cancer, intrahepatic bile duct cancer, oesophageal cancer, pancreatic cancer, stomach cancer, laryngeal cancer, brain cancer, ovarian cancer, testicular cancer, cervical cancer, oral cancer, pharyngeal cancer, renal cancer, thyroid cancer, uterine cancer, urinary bladder cancer, hepatocellular carcinoma, thyroid carcinoma, osteosarcoma, small cell lung cancer, leukaemia, myeloma, gastric carcinoma and metastatic cancers. In a particular aspect of the present invention the complexes are advantageous in the treatment or alleviation of a metastatic cancer. According to a further aspect of the invention we provide the use of a complex of formula I as hereinbefore described in the manufacture of a medicament. More particularly, we provide the use as hereinbefore described in the manufacture of a medicament for the treatment of a proliferative disorder.
According to this aspect of the invention especially provides the use of a complex of formula I as hereinbefore described in the manufacture of a medicament in the form of an aqueous solution. According to a further aspect of the invention there is provided a method of treatment or alleviation of a proliferative disorder which comprises administering to a mammal a therapeutically effective amount of a complex of formula I as hereinbefore described, or a salt thereof. According to this aspect of the invention the method of treatment or alleviation of a proliferative disorder may comprise preparing an aqueous solution of a complex of formula I of the invention.
Determination of the aqueous behaviour of ruthenium c«-tach complexes is important when it comes to understanding the processes involved when these complexes are subjected to biological conditions, most significantly how they will behave in the blood stream and within cells. A key difference between the blood and cytoplasm or nucleus is the chloride concentration, a property which is exploited in cisplatin chemotherapy and the emerging ruthenium complexes. The reduced chloride concentration promotes formation of the reactive aqua species, or the inert hydroxy species, dependent upon the pKa of the aqua complex. The aqua species is then the cytotoxic complex and able to bind to DNA and prevent cell replication.
To simulate the processes in a biological system, two conditions are used - a low chloride concentration (of less than 5 mmol) at physiological pH (typically 6.5 to 7.4) to simulate a cell, and a high chloride concentration (100 mmol) to replicate the blood, where anation is dominant and the parent chloride species persists.
The aqueous chemistry of [RuCl(dppe)(tach)]Cl [15] [CI] was investigated to determine the extent of aquation and the ability of the complex to bind nucelobases, such as guanine. Experiments were performed in 10% D20 / 90% H20 at pH 7.4 10 mM sodium phosphate buffer and monitored by Ή NMR spectroscopy using solvent suppression techniques and {Ή}3,Ρ NMR spectroscopy. All experiments were performed with a concentration of [15] [CI] at 500 uM and chloride concentration was moderated by the addition of sodium chloride, with spectra recorded within 15 minutes of dissolution.
Initially, the aqueous chemistry of [15][C1] was investigated at a high chloride concentration, of 100 mM to model the bloodstream. In the JH NMR and {1H}31P NMR spectra, the parent chloride complex [15] [CI] was observed, along with a second signal, formed by the exchange of the chloride ligand with the solvent - the aquated species. The two complexes are present in approximately 86.5% chloro and 13.5% aquated. The protonated nature of the water bound to the ruthenium is unknown, the ligand may be present as a hydroxy or aqua ligand, or in equilibrium between the two species, dependent upon the pKa of the aqua ligand. Figure 122a: (lH}31P NMR spectra of [15] [CI] in aqueous solution with high (top) and low (bottom) chloride levels.
Figure imgf000035_0001
When in aqueous solution with a low chloride concentration, where no chloride was added (NaCl concentration = 0) the ratio of species changed, with only a single product observed - that of the aquated species. The complex, when within a cell and at concentrations at biological relevance, would be present only as the aquated species, which is the species involved in the interaction with target biomolecules.
The aquation reaction has been observed for all diphosphine complexes in aqueous solution, [14][CI] - [19][C1]. Aquation has also been observed with the case of [RuCl(dmso)2(tach)]Cl [8][C1], however the complex also undergoes ligand exchange between dmso (dimethyl sulphoxide) and water.
The aquation reaction occurring with the diphosphine complexes [14] [CI] - [19] [CI] is observed to reach equilibrium within at most ten minutes from dissolution by Ή NMR and {'H}31? NMR spectroscopy. No changes are observed to solutions over a period of two weeks, with no further species forming. In addition to studying the behaviours of a complex in aqueous medium, the interaction with potential biomolecules was investigated. A potential target biomolecule for ruthenium-tach complexes is DNA, as is the case with classical cytotoxic complexes. The nucleobase which cisplatin predominantly binds to, guanine, has received the most attention and preliminary studies were conducted with [RuCl(dppe)(tach)]Cl [15] [CI] and guanosine. The reaction between [RuCl(dppe)(tach)]Cl and guanosine (Guo) in aqueous solution was investigated by 1H and {!H}31P NMR spectroscopy and performed at a concentration of 10 mM of
[15] [CI]. At equilibrium, the two species observed in the aquation reactions were present (the chloro and aquated species) - however a third species was also observed.
Figure 134-2b herein is a {5H}3IP NMR spectrum of the equilibrium. The additional signals in Figure 12b were attributed to the resultant guanosine complex - [RuCl(dppe)(Guo)(tach)]2Cl, observed as two doublets, arising from the lack of symmetry induced onto the ruthenium centre from the chiral sugar of guanosine. The lack of the symmetry results in the two phosphorus nuclei of the dppe ligand to become inequivalent, exhibit a different chemical shift to each other and to couple through and 4J coupling. The species are observed in the ratio of 24.4% chloro, 30.5% aqua hydroxy and 45.1% guanosine adduct.
The proposed structure of the resulting guanosine complex is depicted in figure 13, with the nucleobase bound to the ruthenium through the N7, as observed with other metallodrugs. The 06 of the guanosine base is likely to form a hydrogen bond to the N¾ group of the cis-tach ligand
Figure imgf000037_0001
Figure 13: Proposed structure for [Ru(dppe)(Guo)(tach)]2Cl
[Ru(dmso-S phen)(<?w-tach)][Cl]2 [11][C1]2, although believed to be aquation resistant due to the poorly labile dmso ligand, was exposed to guanosine to determine its ability to bind to the DNA base. ESI-MS analysis determined that the complex is able to undergo ligand exchange, where the dmso is replaced with guanosine (m/z 347.1). Both aquation products [Ru(OH2)(phen)(cw-tach)]2+ and guanosine adducts [Ru(Guo)(phen)(c/s-tach)]2+ were observed, however with a significant quantity of the starting complex, from either incomplete conversion or an equilibrium preventing further reaction. The Ή NMR spectrum of the reaction mixture contained a set of signals corresponding to [11][CI]2, and the guanosine adduct, [Ru(Guo)(phen)(c/s-tach)]2+. Integrations indicate approximately 85% conversion to the guanosine complex. The complex is proposed to be structurally similar to the corresponding case with [RuCl(dppe)(tach][Cl], [15](C1], with coordination by the N7 and an NH-06 hydrogen bond present between the cw-tach N¾ protons and guanosine.
Figure imgf000038_0001
Figure 1 : Proposed structure for [Ru(Guo)(phen)(cw-tach)] , with NH-0 hydrogen bond between cw-tach and guanosine. R = ribose of guanosine.
The activity of a complex according to the present invention can be assessed by the following in vitro ά in vivo methods. Cell lines and MTT Assay
The MTT assay is a colourimetric assay used to determine the cytotoxicity of a compound. Cells are treated with various concentrations of drug, typically ranging between 0.1 and 300 uM, with positive (no ceils added, 0% viability) and negative (untreated cells, J 00% viability) controls. After incubation, the water soluble MTT dye is added and viable cells allowed to metabolize the MTT to insoluble purple formazan crystals. After removal of cell culture medium, the formazan product is solvated by dmso and the amount produced determined by optical absorbance at λ = 540 rum. As only viable cells are capable of metabolizing the substrate, the number of viable cells is proportional to the amount of MTT formazan produced.
Figure imgf000039_0001
The activity of the compound is calculated as the IC50 - the concentration of drug required to inhibit MTT formazan production by 50 % , and thus to inhibit the growth of cells by 50 %, through a dose-response curve, with each value at a given concentration calculated as a percentage of cell viability compared to the positive and negative controls.
MTT assays were performed using the A549 human non-small cell lung adenocarcinoma and A2780 human ovarian adenocarcinoma cell lines. Both cell lines are available from the European Collection of Cell Cultures (ECACC), Health Protection Agency. Specific methodology for conducting the assays is referred to in the examples herein.
There is further provided a pharmaceutical composition comprising a complex of formula I as hereinbefore described, in free form or in pharmaceutically acceptable salt form, in association with a pharmaceutically acceptable adjuvant, diluent or carrier. The pharmaceutical compositions for separate administration of the combination partners and for the administration in a fixed combination, i.e., a single galenical composition comprising at least two combination partners, according to the invention can be prepared in a manner known per se and are those suitable for enteral, such as oral or rectal, and parenteral administration to mammals, including man, comprising a therapeutically effective amount of at least one pharmacologically active combination partner alone or in combination with one or more pharmaceutically acceptable carriers, especially suitable for enteral or parenteral application. Pharmaceutical compositions contain, e.g., from about 0.1% to about 99.9%, preferably from about 20% to about 60%, of the active ingredients. Pharmaceutical preparations for the combination therapy for enteral or parenteral administration are, e.g., those in unit dosage form, such as tablets including sugar-coated tablets, capsules, suppositories and ampoules. These are prepared in a manner known, per se, e.g., by means of conventional mixing, granulating, sugar-coating, dissolving or lyophilizing processes. It will be appreciated that the unit content of a combination partner contained in an individual dose of each dosage form need not in itself constitute an effective amount since the necessary effective amount can be reached by administration of a plurality of dosage units.
The pharmaceutical composition can be formulated for particular routes of administration such as oral administration, parenteral administration, and rectal administration, etc. In addition, the pharmaceutical compositions of the present invention can be made up in a solid form including capsules, tablets, pills, granules, powders or suppositories, or in a liquid form including solutions, suspensions or emulsions. The pharmaceutical compositions can be subjected to conventional pharmaceutical operations such as sterilization and/or can contain conventional inert diluents, lubricating agents, or buffering agents, as well as adjuvants, such as preservatives, stabilizers, wetting agents, emulsifiers and buffers etc.
Certain injectable compositions are aqueous isotonic solutions or suspensions, and suppositories are advantageously prepared from fatty emulsions or suspensions. Said compositions may be sterilized and/or contain adjuvants, such as preserving, stabilizing, wetting or emulsifying agents, solution promoters, salts for regulating the osmotic pressure and/or buffers. In addition, they may also contain other therapeutically valuable substances. Said compositions are prepared according to conventional mixing, granulating or coating methods, respectively, and contain about 0.1-75%, or contain about 1-50%, of the active ingredient. Preferably, the pharmaceutical composition according to this aspect of the invention is in the form of an aqueous solution.
For the above-mentioned indications, the appropriate dosage will of course vary depending upon, for example, the complex employed, the host, the mode of administration and the nature and severity of the condition being treated. However, in general, satisfactory results in animals are indicated to be obtained at a daily dosage of from about 0.1 to about 100 mg kg, preferably from about 1 to about 30 mg/kg animal body weight. In larger mammals, for example humans, an indicated daily dosage is in the range from about 1 to about 500 mg, preferably from about 1 to about 100 mg of an agent of the invention, conveniently administered, for example, in divided doses up to three times a day or in sustained release form.
The complexes or compositions of the invention may be administered by any conventional route, in particular enterally, preferably orally, for example in the form of tablets or capsules, or parenterally, for example in the form of injectable solutions or suspensions.
The complexes according to the invention have an antiproliferative effect with respect to tumoral cells. They are useful for treating cancers by inducing apoptosis in tumoral cells.
Furthermore, the complexes according to the invention are particularly advantageous for treating tumours which are resistant to cisplatinum or to other anticancer drugs. The complexes or compositions according to the invention can be administered in different ways and in different forms. Therefore, they can be administered systemically, orally, by inhalation or by injection, for example intravenously, intramuscularly, subcutaneously, transdermically, intra-arterially, etc., the intravenous, intramuscular, subcutaneous, oral and inhalation methods being preferred. For the injections, the complexes are generally conditioned in the form of liquid suspensions, which can be injected by means of syringes or perfusions, for example. However, the complexes of the invention are significantly more water soluble than other anticancer drugs, such as, cisplatin, and may generally be dissolved in saline, physiological, isotonic, buffered etc. solutions, compatible with pharmaceutical use and known to the person skilled in the art. The complexes of the present invention have generally been found to be soluble at least to 1 mM in water or phosphate buffered saline (PBS) at room temperature. However, some diphosphanes, i.e. those in which a pair of any two of V, L2 and L3 comprise a moiety -R2 !R22P-(CHR23)m-PR24R25, such as the dppe complex
Figure imgf000043_0001
triaminocyclohexane-K Ν,Ν',Ν") ruthenium(II) chloride— hydrate
([RuCl(dppe)(tach)]Cl), have a higher solubility, e.g. up to 10-30 mM. The bis dmso complexes, i.e. those in which at least two of L1, L2 and L3 represent -S(0)R1 R15, such as chlorobis(dimethylsulfoxide-K.¾(ci5;-ci5-1 ,5-triaminocyclohexane- κ^Ν,Ν',Ν") ruthenium(n) chloride ([RuCl(dmso)2(tach)]Cl), have a solubility of greater than 300mM.
Therefore, the compositions can contain one or more agents or vehicles chosen from dispersants, solubilisers, stabilisers, preservatives, etc. Agents or vehicles which can be used in liquid and/or injectable formulations are in particular methylcellulose, hydroxymethylcellulose, carboxymethylcellulose, polysorbate 80, mannitol, gelatin, , lactose, vegetable oils, acacia, etc.
The complexes can also be administered in the form of gels, oils, tablets, suppositories, powders, capsules, aerosols, etc., possibly by means of galenic forms or devices guaranteeing prolonged and/or delayed release. For this type of formulation, it is advantageous to use an agent such as cellulose, carbonates or starches.
The throughput and/or the dose injected can be adapted by the person skilled in the art dependently upon the patient, the pathology in question, the administration method, etc. Typically, the complexes are administered at doses which can vary between 0.1 and 100 mg/kg body weight, and more generally between 0.01 and 10 mg kg, typically between 0.1 and 10 mg/kg. Furthermore, repeated injections can be given, should the occasion arise. On the other hand, for chronic treatments, delay or prolongation systems can be advantageous.
The invention also concerns a method for treating a pathology linked to cell hyperproliferation, in particular a cancer, by administering to a subject suffering from this type of pathology an effective quantity of one of the complexes according to the invention.
Within the context of the invention, the term "treatment" means the preventive, curative, palliative treatment as well as patient care (reduction of suffering, improvement of life span, slowing down the progression of the illness, reducing the tumoral growth, etc.). Furthermore, the treatment can be implemented in combination with other agents or chemical or physical treatments (chemotherapy, radiotherapy, gene therapy, etc.). The treatments and drugs of the invention are particularly intended for humans.
Therefore, the complexes according to the invention can advantageously be used in combination with an anti-cancer treatment implementing radiation, such as radiotherapy and brachytherapy. The radiation applied involves in particular X rays, gamma rays, ionising particles such as electrons, neutrons or carbon ions.
According to another aspect of the invention there is provided a pharmaceutical composition comprising a complex of formula I, in free form or in pharmaceutically acceptable salt form, in combination with another therapeutically active ingredient, optionally in association with a pharmaceutically acceptable adjuvant, diluent or carrier. According to this aspect of the invention, the complexes according to the invention can be used with other chemical agents or therapeutic anti-cancer treatments, such as the following therapeutic chemical agents: cisplatinum, carboplatinum, NCS (neocarzinostatin), Taxotere® or Taxol®, advantageously NCS or Taxol®. The complexes according to the invention are preferably conditioned and administered in combination, separately or sequentially in relation to other agents or therapeutic treatments.
Complexes of the present invention may be usefully combined with another pharmacologically active compound, or with two or more other pharmacologically active compounds, particularly in the treatment of cancer. For example, a complex of the present invention, as defined above, may be administered simultaneously, sequentially or separately in combination with one or more agents selected from chemotherapy agents, e.g. mitotic inhibitors such as a taxane, a vinca alkaloid, paclitaxel, docetaxel, vincristine, vinblastine, vinorelbine or vinflunine, and other anticancer agents, e.g. cisplatin, 5-fluorouracil or 5-fluoro-2-4(l H, 3H)-pyrimidine dione (5FU), flutamide or gemcitabine. Such combinations may offer significant advantages, including synergistic activity, in therapy.
A complex of the present invention may also be used to advantage in combination with other antiproliferative compounds. Such antiproliferative compounds include, but are not limited to aromatase inhibitors; antiestrogens; topoisomerase I inhibitors; topoisomerase Π inhibitors; microtubule active compounds; alkylating compounds; histone deacetylase inhibitors; compounds which induce cell differentiation processes; cyclooxygenase inhibitors; MMP inhibitors; mTOR inhibitors; antineoplastic antimetabolites; plat in compounds; compounds targeting/decreasing a protein or lipid kinase activity and further anti- angiogenic compounds; compounds which target, decrease or inhibit the activity of a protein or lipid phosphatase; gonadorelin agonists; anti-androgens; methionine aminopeptidase inhibitors; bisphosphonates; biological response modifiers; antiproliferative antibodies; heparanase inhibitors; inhibitors of Ras oncogenic isoforms; telomerase inhibitors; proteasome inhibitors; compounds used in the treatment of hematologic malignancies; compounds which target, decrease or inhibit the activity of Fit-3; Hsp90 inhibitors, such as 17-allyIamino-gelda-namycin and 17-dimethylaminoethylamino- 17-demethoxy-geldana-mycin; temozolomide; kinesin spindle protein inhibitors or pentamidine/chlorpromazine; PI3 inhibitors, RAF inhibitors, EDG binders, antileukemia compounds, ribonucleotide reductase inhibitors, S-adenosylmethionine decarboxylase inhibitors, antiproliferative antibodies or other chemotherapeutic compounds. Further, alternatively or in addition they may be used in combination with other tumour treatment approaches, including surgery, ionizing radiation, photodynamic therapy, implants, e.g. with corticosteroids, hormones, or they may be used as radiosensitizers. Also, in anti-inflammatory and/or antiproliferative treatment, combination with anti-inflammatory drugs is included. Combination is also possible with antihistamine drug substances, bronchodilatory drugs, NSAJD or antagonists of chemokine receptors. The present invention also concerns a method for inhibiting in vivo, in vitro or ex vivo the proliferation of tumoral cells including placing said tumoral cells in contact with one of the products according to the invention. The tumoral cells can in particular originate from the pathologies specified above. The method may, in particular, comprise the apoptosis of tumoral cells.
Acid addition salts may be produced from the free bases in known manner, and vice- versa. A pharmaceutically acceptable salt is any salt of the parent complex that is suitable for administration to an animal or human. A pharmaceutically acceptable salt also refers to any salt which may form in vivo as a result of administration of an acid, another salt, or a prodrug which is converted into an acid or salt. A salt comprises one or more ionic forms of the complex, such as a conjugate acid or base, associated with one or more corresponding counter-ions. Salts can form from or incorporate one or more deprotonated acidic groups (e.g. carboxylic acids) one or more protonated basic groups (e.g. amines), or both (e.g. zwitterions).
As used herein, the term "pharmaceutically acceptable salts" refers to salts that retain the biological effectiveness and properties of the complexes of this invention and, which are not biologically or otherwise undesirable. In many cases, the complexes of the present invention are capable of forming acid and/or base salts by virtue of the presence of amino and/or carboxyl groups or groups similar thereto. Pharmaceutically acceptable acid addition salts can be formed with inorganic acids and organic acids, e.g., acetate, aspartate, benzoate, besylate, bicarbonate/carbonate, bisulphate/sulphate, borate, camsylate, citrate, edisylate, esylate, formate, fumarate, gluceptate, gluconate, glucuronate, hexafluorophosphate, hibenzate, hydrochloride/chloride, hydrobromidefaromide, hydroiodide/iodide, isethionate, lactate, malate, maleate, malonate, mesylate, methylsulphate, naphthylate, 2- napsylate, nicotinate, nitrate, orotate, oxalate, palmitate, pamoate, phosphate hydrogen phosphate/dihydrogen phosphate, saccharate, stearate, succinate, tartrate, tosylate and trifluoroacetate salts. Inorganic acids from which salts can be derived include, for example, hydrochloric acid, hydrobromic acid, sulphuric acid, nitric acid, phosphoric acid, hexafluorophosphoric acid, and the like. Thus, a preferred counter ion for use in association with the complex of formula I of the invention is halide, e.g. fluoride, chloride, bromide and iodide, chloride is preferred.
Organic acids from which salts can be derived include, for example, acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p- toluenesulfonic acid, salicylic acid, and the like. Pharmaceutically acceptable base addition salts can be formed with inorganic and organic bases. Inorganic bases from which salts can be derived include, for example, sodium, potassium, lithium, ammonium, calcium, magnesium, iron, zinc, copper, manganese, aluminium, and the like; particularly preferred are the ammonium, potassium, sodium, calcium and magnesium salts. Organic bases from which salts can be derived include, for example, primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines, basic ion exchange resins, and the like, specifically such as isopropylamine, trimethylamine, diethylamine, triethylamine, tripropylamine, and ethanolamine. The pharmaceutically acceptable salts of the present invention can be synthesized from a parent complex, a basic or acidic moiety, by conventional chemical methods.
Accordingly, as used herein a complex of the present invention can be in the form of one of the possible isomers, rotamers, atropisomers, tautomers or mixtures thereof, for example, as substantially pure geometric (cis or trans) isomers, diastereomers, optical isomers (antipodes), racemates or mixtures thereof.
Certain isotopically-labelled complexes of formula (I), for example, those incorporating a radioactive isotope, are useful in drug and/or substrate tissue distribution studies. The radioactive isotopes tritium, i.e. 3H, and carbon-14, i.e. C, are particularly useful for this purpose in view of their ease of incorporation and ready means of detection. Substitution with heavier isotopes such as deuterium, i.e. 2H, may afford certain therapeutic advantages resulting from greater metabolic stability, for example, increased in vivo half-life or reduced dosage requirements, and hence may be preferred in some circumstances. Substitution with positron emitting isotopes, such as nC, I8F, 150 and 1 N, can be useful in Positron Emission Topography (PET) studies for examining substrate receptor occupancy.
Isotopically-labelled complexes of formula (I) can generally be prepared by conventional techniques known to those skilled in the art or by processes analogous to those described in the accompanying Examples and Preparations using an appropriate isotopically-labelled reagents in place of the non-labelled reagent previously employed. According to an additional aspect of the invention we provide a process for the manufacture of a complex of formula I as hereinbefore described which comprises one or more of the following steps;
(a) reacting a compound of formula Π;
Figure imgf000050_0001
Lv, L2 and L are each as hereinbefore defined;
L4a, L5a and L6a are each a leaving ligand, such as halo, dmso, etc.; with a compound of formula HI;
Figure imgf000050_0002
in which R1, R2, R3, R4, R5, R6, R7, R8 and R9, are each as hereinbefore defined; or (b) reacting a complex of formula IV;
Figure imgf000051_0001
in which R1, R2, R3, R4, R5, R6, R7, R8 and R9, are each as hereinbefore defined; and at least one of Lla, L2a and L3a is a leaving ligand, selected from the group consisting of halo, dmso and -PR28R29R30;
R28, R29 and R30, which may be the same or different, are each alkyl CI to 20, aryl (optionally substituted by one or more alkyl CI to 20), amino or -OR31;
R31 is hydrogen or alkyl CI to 20; and
the remainder of Lia, L2a and L3a, which may be the same or different, each have the same meaning as L1, L2 and L3 respectively or may be selected from the group consisting of halo, dmso and -PR28R29R30;
with one or more compounds comprising ligands LIs L2 and L3 wherein Ll3 L2 and L3 are each as hereinbefore defined.
Complexes of formula IV as hereinbefore defined are novel per se and are useful as intermediates in the preparation of complexes of formula I.
Therefore, according to a further aspect of the invention there is provided a complex of formula IV:
Figure imgf000052_0001
in which,
R1, R2, R3, R4, R5 and R6, which may be the same or different are each, hydrogen or alkyl CI to 20, alkenyl CI to 20, aryl, alkyl(ci to 20)aryl, alkenyl(C] to 20)aryl, heteroaryl, a sugar, an amino acid, a nucleoside, a nucleotide or a peptide;
R7, R8 and R9, which may be the same or different are each, hydrogen or alkyl CI to 20; and
at least one of Lia, L2a and is a leaving ligand, selected from the group consisting of halo, dmso and -PR28R29R30;
R28, R29 and R30, which may be the same or different, are each alkyl CI to 20, aryl (optionally substituted by one or more alkyl CI to 20), amino or -OR31;
R31 is hydrogen or alkyl CI to 20; and
the remainder of Lla, L2a and L3a, which may be the same or different, each have the same meaning as L1, L2 and L3 respectively or may be selected from the group consisting of halo, dmso and -PR28R 9R30;
and isomers thereof;
in free or in salt form. For purposes of interpreting this specification, the following definitions will apply and whenever appropriate, terms used in the singular will also include the plural and vice versa. The invention will now be described by way of example only and with reference to the accompanying figures in which:
Figure 12a: illustrates the {'Η}3^ NMR spectra of [15] [CI] in aqueous solution with high (top) and low (bottom) chloride levels; and
Figure 12b: illustrates the {Ή}3 ΙΡ NMR spectrum of the equilibrium.
Figure 15 illustrates the DNA structural distortions from a) intrastrand 1,2 d(GpG), b) intrastrand 1,3 d(GpG) and c) interstrand l,2d(GpG) platination by cisplatin. Diagrams from ref [48]
The binding of cisplatin to DNA results in a bend towards the major groove of DNA of 30 to 60 ° and unwinds the helix (up to 23 °).49 The structural distortion stalls DNA synthesis, from either the physical block of RNA polymerases from the platinum complex, the binding of proteins to the platinated DNA, such as transcription factor proteins, or disruption of the nucleosomal structure 48 Following inhibition of transcription, DNA damage response is activated, which is mainly induced by the p53 protein, inducing cell cycle arrest, and the eventual mechanism of apoptosis (programmed cell death).50 Figure 16 illustrates the cell viability plots for the A549 cell line with cisplatin, [X16]C1 and [X17]C1; and
Figure 17 illustrates the cell viability plots for the A2780 cell line with cisplatin, [X16]CI and [X17JC1.
Experimental
Synthesis
Unless otherwise states, all reagents were purchased from Sigma-Aldrich UK and solvents from Fisher Scientific). NMR spectra were obtained using either a Jeol ECS 400, Jeol EXC 400 (Ή 399.78 MHz, 3 IP 161.83, 13C 100.52) at 293 K or a Bruker Avance 500 spectrometer (Ή 500.23 MHz, 31P 202.50, I3C 125.78) at 295 K. JR spectra were recorded on a Unicam (Research Series) FTIR using SensIR Technologies ATR equipment. High resolution mass spectrometry was performed by the University of York mass spectrometry service using the ESI technique on a Bruker Daltronic microTOF instrument. Elemental analyses were performed by the University of York Microanalytical service.
Synthesis of starting materials
Cis,cis- 1,3,5-triaminocyclohexane (c«-tach),41 dichlorotris (triphenylphosphane) ruthenium(n)51, dicWoro| ¾c-tjis(dimethylsulfoxide-K5)](dimethylsuIfoxide-KG) ruthenium(II)52 and chloro-mer-trisacetonitrile^4-cycloocta-l,5-diene) ruthenium(II) hexafluorophosphate53 were prepared according to literature procedures. The Di-μ- chloro(n4-l,5-cyclooctadiene)ruthemum(II) used was previously synthesised by the Lynam research group according to the literature procedure53. All chemicals used were purchased from Sigma-Aldrich UK, with the exception of cis-cis-\, 3,5- Cyclohexanetncaboxylic acid (TCI UK) and ruthenium trichloride hydrate (Precious Metals Online).
Synthesis of ruthenium (Π) cis-tach complexes with triphenylphosphine ligands All reactions were performed under an atmosphere of dry nitrogen using standard Schlenk line and glove box techniques. Dichloromethane, acetonitrile and pentane were purified with an Innovative Technologies anhydrous solvent engineering system. Diethyl ether was dried over sodium, and c/2-dichloromethane over calcium hydride and vacuum transferred prior to use. All other chemicals were purchased from Sigma- Aldrich UK.
Example 1
ChIoro(ci cis-l,3,5-triaminocyclohexane- 3N,JV,,N")bis(triphenyl
phosphane)ruthenium(IJ) hexafluorophosphate [1]PF6
Figure imgf000056_0001
cis-cis- 1,3,5-triaminocyclohexane (13 mg, 0.1 mmol) was added to a schlenk charged with dichlorotris(triphenylphosphane)ruthenium(n) (100 mg, 0.1 mmol) in dichloromethane (20 mL) and stirred for 45 minutes, after which, sodium hexafluorophosphate (20.8 mg, 0.125 mmol) was added and stirred for 8 hours. The precipitate was removed by filtration and the product precipitated by the addition of pentane. The solvent was filtered off, and the pale orange powder was washed twice with pentane. Yellow crystals were obtained by slow diffusion of pentane into a dichloromethane solution.
NMR Spectroscopy
Figure imgf000056_0002
Cs mirror plane
lR NMR (CD2Ch, 399.8 MHz, 293K) δ 7.43 app. t, HP = 10 Hz, HH = 7.5 Hz,
VHH = 1.5 Hz, 12H, FPfo, Ar2), 7.37 (m, 6H, ?Ph Ar4), 7.25 (tt, HH = 7.6 Hz, HH = 1.5 Hz, 12H, ?Ph3, Ar3), 3.57 (d, 2Jm = 11.8 Hz, 2H, N¾, N2), 3.44 (d, 2Jm = 11.8 Hz, 2H, NH2, N2), 3.27 (s, 2H, CH, Cy2), 2.96 (s, 1Η, CH, Cy1), 2.15 (s, 2Η, NH2, N1), 1.97 (d, 2JHH = 15.7 Hz, 1H, CH2, Cy4), 1.91 (d, 2Jm = 15.7 Hz, 1H, CH2, Cy4), 1.77 (d, HH = 1 .0 Hz, 2H, CH2, Cy3), 1.42 (d, 2Jm = 1 .0 Hz, 2H, CH2, Cy3);
31P NMR (CD2C12, 161.8 MHz, 293K) δ 47.28 (s, 2P, P? ) -144.67 (septet, IP, PF6); 13C NMR (CD2C12, 100.5 MHz, 293K) δ 134.5 (t, |2JPC + 4JPC| = 9.5 Hz, Ρ/>Λ3ϊ Ar2), 133.1 (t, ( pc + VPCI = 37 Hz, P/¾ Ar1), 130.7 (s, Ph^, Ar4), 129.3 (t, |3JPC + 5JPC| = 8.8 Hz, Ρ Λ3, Ar3), 43.0 (s, CH, Cy2), 42.8 (s, CH, Cy1), 35.0 (s, C¾, Cy4), 33.3 (s, CH2, Cy3).
Mass Spectrometry
ESI-MS: m/z 790.1826 ([RuCl(K3-c/5-tach)(PPh3)2]+, Calc 790.1815, 100 %), 941.2051 ([Ru(NCMe)(K3-cis-tach)(PPh3)2PF6] +, Calc 941.2039, 7.4).
Example 2
Dichloroidi-cw-ljSjS-triaminoc clohexane- ^ V'jiV'^triphen lphosphaBe ruthenium(II)— dichloromethane [2]
Figure imgf000057_0001
cis-cis- 1,3,5-triaminocyclohexane (30.0 nig, 0.232 mmol) was added to an ampoule charged with dichlorotris(triphenylphosphane)ruthenium(II) (196 mg, 0.204 mmol) dissolved in dichloromethane (20 mL), causing an instant colour change from black to orange. The solution was stirred at 50°C for 4 days in the sealed vessel, during which time the solution changed colour to yellow and a white precipitate formed. The precipitate was removed by filtration and the filtrate reduced in volume to approx. 1 mL in vacuo. The product was precipitated by addition of pentane (20 mL) as an orange powder, and washed twice with pentane (20 mL). Yield: 115 mg (86.8 %, 0.177 mmol of RuCl2(K3-c -tach)(PPh3).CH2Cl2).
NMR Spectroscopy
Figure imgf000058_0001
Cs minor plane
H NMR (CD2C12, 399.8 MHz, 293K) δ 7.85 (app t, HH = 7.5 Hz, VHP = 5.8 Hz,
VHH = 1.5 Hz, 6H, P/Vz3, Ar2), 7.36 (m, 9H, Ρ/>Λ3, Ar3 + Ar4), 4.77 (s, 2H, NH2, N1), 3.90 (bs, 1Η, CH, Cy1), 2.92 (s, 2Η, CH, Cy2), 2.65 (d, VHH = 10.6 Hz, 2H, N¾ N2),
1.92 (s, 4H, CH2, Cy3), 1.85 (d, HH = 10.6 Hz, 2H, NH2, N2), 1.62 (d, VHH = 15.3
Hz, 1H, CH2, Cy4), 1.00 (d, VHH = 15.3 Hz, 1H, CH2, Cy4);
31Ρ{Ή} NMR (CD2C12, 161.8 MHz, 293 ) δ 66.0 (s, IP, PPh3);
"Ci'H} NMR (CD2C12, 100.5 MHz, 293K) δ 136.2 (d, 'Jpc = 36.0 Hz, VPh3, Ar1), 134.2 (d, VPC = 10.1 Hz, VPh3, Ar2), 129.5 (d, VPC = 1.85 Hz, ?P 3, Ar4), 128.8 (d,
VPC = 8.7 Hz, ?Ph3, Ar3), 44.0 (s, CH, Cy1), 43.8 (s, CH, Cy2), 35.0 (s, CH2, Cy3),
33.6 (s, CH2, Cy4). Mass Spectrometry
ESI-MS: m/z 569.1186 ([RuCl(NCMe)( 3-c i-tach)(PPh3)l+. Calc 569.1173, 100 %), 528.0919 ([RuCl(K3-c«-tach)(PPh3)]+ ; 528.0907, 25), 246.5607 ([RU(K3-CW- tach)(PPh3)]2+, 246.5608, 10). Infra-Red Spectroscopy
ATR-IR: (cm 1) 3462, 3283, 3240, 3050, 2888, 1649, 1588, 1480, 1432 (P-Ph), 1367, 1346, 1270, 1211, 1183, 1156, 1089, 1027, 968, 905.
Elemental Analysis
# CH2C12 c / % H / % N / %
Found 46.25 4.92 6.43
0 51.15 5.37 7.46
1 46.31 4.97 6.48
Table 0.1: CHN Elemental analysis for RuCl2(K3-cw-tach)(PPh3)
Figure imgf000059_0001
Example 3 μ-Chloro-dichloro-lκ1C ,2κ1C -[bis(ί?M^-cί -l,3,5-triaminoc cIolle ane)-
Figure imgf000059_0002
tetrapheaylborate— dichloromethane [3] [BPh4]
Figure imgf000059_0003
Sodium tetraphenylborate (44.2 mg, 0.129 mmol) was added to a solution of [2] (65.5 mg, 0.101 mmol) in dichloromethane (20 mL) and allowed to stir for 6 hours. The precipitate was removed by filtration and the product crystallised by slow diffusion of pentane (100 mL). The crystals isolated by filtration and dried in vacuo. Yield: 43.2 mg (56 %, 0.014 mmol of [{RuCl( 3-cw-tach)(PPh3}2(Jci-Cl)][BPh4].l½CH2Cl2).
NMR Spectroscopy
Figure imgf000060_0001
¾ NMR (CD2C12, 399.8 MHz, 293K) S 7.70 (m, 12H, PPA3), 7.29 (m, 26H, P A3, BPh4), 7.00 (m, 8H, BPh4), 6.85 (m, 4H, BPh4), 6.73 (d, 2Jm = 10.5 Hz, 2H, NH2, N1), 4.24 (d, JHH = 10.5 Hz, 2H, NH2, N1), 3.93 (m, 2Η, CH, Cy1), 2.90 (s, 2Η, CH, Cy2), 2.67 (d, 2JHH = 1 1.6 Hz, 2H, NH2, N2), 2.62 (s, 2Η, CH, Cy3), 2.39 (d, HH = 11.6 Hz, 2H, NH2, N2), 1.96 (m, 8Η, CH2 Cy4 + Cy6), 1.87 (d, HH = 10.7 Hz, 1H, NH2, N3), 1.52 (d, 2JHH = 15.8 Hz, 1H, CH2, Cy5), 0.80 (d, HH = 10.7 Hz, 1H, NH2, N3), 0.70 (d, 2JHH = 15.8 Hz, 1H, CH2, Cy5);
"P^H} NMR (CD2CI2, 161.8 MHz, 293K) δ 60.3 (s, 2P, _PPh3);
nC{lU} NMR (CD2CI2, 100.5 MHz, 293K) δ 136.4 (s, BPh4), 135.2 (d, ]JPC = 35.5 Hz, Ρ_?Λ3> Ar1), 133.6 (d, 2JPC = 9.8 Hz, ΡΡΛ3 Ar2), 130.0 (s, PPhj, Ar4), 129.0 (d, 3JPC = 8.6 Hz, PPh3, Ar3), 126.1 (m, BPhA), 122.3 (s, BPh , 43.9 (s, CH, Cy'), 43.65 (s, CH, Cy3), 43.6 (s, CH, Cy2), 35.1 (s, CH2), 34.2 (s, C¾), 33.0 (s, C¾).
Mass Spectrometry
ESI-MS: m/z 191.1496 ([{RuCl(K3-c«-tach)(PPh3}2C"-Cl)], Calc 1901.1502, < 1 %), 569.1175 ([RuCl(NCMe)(K3-cis-tach)(PPh3) ; 569.1173, 100), 28.0896 ([RUC1(K3- cis-tach)(PPh3)]+ , 528.0907, 20). Infra-Red Spectroscopy
ATR-IR: (cm-') 3281, 3237, 3137, 3049, 2896, 1590, 1480, 1434 (P-Ph), 1265, 1158, 1092, 1027, 03.
Elemental Analysis
# CH2C1Z C / % H / % N / %
Found 57.72 5.51 5.38
0 61.30 5.72 5.96
1 58.62 5.53 5.62
1.5 57.40 5.43 5.46
2 56.23 5.36 5.23
Table 0.2: CH Elemental analysis for [{RuCl(KJ-cM-tachXPPh3}20«-Cl)][BPh4] [3][BPh4], C72H8oBCI3N6P2Ru2.
Example 4 AcetonitrilechloroicM'-c/i-l^^-trianiinocyclohexane- 'NjiV'A^") tripbenylphosphaneruthenium(II) hexafluorophosphate [4][PF6]
Figure imgf000061_0001
To a mixture of [2] (55.5 mg 0.085 m ol) in acetonitrile (20 mL) was added sodium hexafluorophosphate (18.0 mg, 0.107 mmol). The resulting pale yellow solution was stirred for 30 mins until all solid had dissolved. After, the solvent was removed in vacuo, and the residue taken up in dichloromethane (10 mL). The insoluble salt was removed by filtration, and the pale cream product precipitated out on addition of diethyl ether (50 mL), The product was isolated by filtration and washed a further time with diethyl ether (20 mL). Yield: 48.3 mg (70.6 %, 0.060 mmol of
[RuCl(NCMe)(K3-cw-tach)(PPh3)][PF6]).
NMR Spectroscopy
Figure imgf000062_0001
*H NMR (CD2CI2, 399.8 MHz; 293 ) δ 7.75 (tn, 6H, ?Ph3, Ar2), 7.45 (m, 9H, ΡΡΛ3, AT3 + Ar4), 4.12 (m, 2H, NH2, N1), 3.77 (m, IH, CH Cy'), 3.12 (s, 1Η, CH, Cy2), 3.05 (d, 2JHH = 12.0 Hz, IH, NH2, N2), 2.89 (s, 1Η, CH, Cy3), 2.85 (d, 2Jm = 12.0 Hz, IH, NH2, N3), 2.49 (d, VHH = 12.2 Hz, IH, NH2, N2), 2.29 (s, 3Η, CHjCN), 2.15 (d, 2JHH = 15.5 Hz, IH, CH2, Cy6), 1.96 (m, 2Η, CH2, Cy ),1.85 (d, HH = 15.5 Hz, IH, C¾ Cy6), 1.68 (d, VHH = 15.4. 2.0 Hz, IH, CH2, Cy3), 1.30 (d, HH = 12.1 Hz, IH, NH2, N3), 1.00 (d, VHH = 15.4. 2.0 Hz, IH, CH2, Cy5);
31P{XH} NMR (CD2C12, 161.8 MHz, 293K) S 60.61 (s, IP, Ph3), -144.67 (septet, IP,
,3C{1H} NMR (CD2CI2, 100.5 MHz, 293K) δ 133.8 (d, VPC = 38.7 Hz, PPh3, Ar1), 133.7 (d, VPC = 9.9 Hz, PP¾, Ar2), 130.5 (d, Vrc = 2.1 Hz, PP¾, Ar4), 129.5 (d, VPC = 8.8 Hz, PPh Ar3), 126.4 (s, NCC¾), 43.8 (s, CH, Cy1), 43.6 (s, CH, Cy3), 43.4 (s, CH, Cy2), 34.8 (s, CH2, Cy4), 33.5 (s, CHZ, Cy5 + Cy6), 4.7 (s, NCO¼).
Mass Spectrometry
ESI-MS: m/z 720.1416 ([Ru(NCMe)2(K3-cii-tach)(PPh3XPF6)r, Calc 720.1393, 2 ), 569.1167 ([RuCl(NCMe)(K3-cw-tach)(PPh3)]+, 569.1173, 100), 528.0909 ([RUC1(K3- cis-tach)(PPh3)]+, 528.0907, 5), 287.5866 ([Ru( CMe)2(K3-c/5-tachXPPh3)]2+, 287.5874, 25), 267.0733 (rRu(NCMeXK -m-tach)(PPh3)r+, 267.0741, 35), 246.5603 (rRu(K3-cis-tach)(PPh3)]2+, 246.5608, 25). Iofra-Red Spectroscopy
ATR-IR. (cm"1) 2249 (CNN), 1596, 1482, 1436 (P-Ph), 1367, 1270, 1174, 1140, 11 18, 1009, 915, 838 (PF6 ").
Elemental Analysis
# Solvent C / % H / % N / %
Found 43.39 4.61 6.61
0 43.73 4.66 7.85
½ C¾Cb + ½ Et20 43.14 4.95 7.06
[411PF,;], C25H33ClF6N4P2Ru.
Example 5
Bisacetonitrile(cis-ci l,3,5-triaminocyclohexane-K3N,N', V'')triphenylphosphane ruthenium(H) hexafluorophosphate [5)ΓΜ )2
Figure imgf000063_0001
A mixture of sodium hexafluorophosphate (37.8 mg, 0.225 mmol) and [2] (56.1 mg, 0.086 mmol) were heated under reflux in acetonitrile for 4 hours. After, the solvent was removed in vacuo, and the product extracted in dichloromethane (40 mL). The insoluble salt was removed by filtration, and the filtrate concentrated to 10 mL. The white product was precipitated out by addition of diethyl ether (50 mL), collected by filtration, washed with diethyl ether (20 mL) and dried in vacuo. Yield: 38.1 mg (51.2 %, 0.044 mmol of [RuCl(NCMe)2( 3-c«-tach)(PPh3)][PF6]2)
NMR Spectroscopy
Figure imgf000064_0001
Cs mirror plane *H NMR (CD2C12, 399.8 MHz, 293K) δ 7.53 (m, 15H, P/»A3, Ar2 + Ar3 + Ar4), 3.82 (s, 2H, NH2, N1), 3.74 (s, 1H, CH, Cy1), 3.36 (d, HH = 12.5 Hz, 2H, NH2, N2), 3.06 (s, 2Η, CH, Cy2), 2.40 (s, 3Η, CH3CN), 2.21 (d, HH = 15.2 Hz, 2H, NH2, N2), 1.92 (m, 4Η, Cy3), 1.70 (d, HH = 15.6 Hz, 1H, CH2, Cy4), 0.85 (d, HH = 15.6 Hz, 1H, CH2, Cy4);
31Ρ{Ή} NMR (CD2C12, 161.8 MHz, 293K) δ 55.93 (s, IP, Ph3), -144.67 (septet, IP, F6);
13C{'H} NMR (CD2C12, 100.5 MHz, 293K) δ 133.2 (d, 2JPC = 10.1 Hz, PPA3, Ar2), 131.6 (d, pc = 2.4 Hz, PPA3, Ar4), 131.5 (d, VPC = 42.6 Hz, PPh3, Ar1), 130.2 (d, 3JPC = 9.3 Hz, PPA3, Ar3), 43.9 (s, CH, Cy1), 43.2 (s, CH, Cy2), 33.4 (s, CH2, Cy4), 33.2 (s, CH2, Cy3), 4.8 (s, NCC%).
Mass Spectrometry
ESI-MS: m/z 720.1372 ([Ru(NCMe)2(K3-cw-tachXPPh3).PF6]+, Calc 720.1395, 100
%). Example 6
Figure imgf000065_0001
triphenyIphosphaneruthenium(II) chloride— hydrate [6] [CI]
([RuCI(dmso)(tach)(PPh3)]CI)
Figure imgf000065_0002
An orange mixture of [2].CH2Ch (56.4 mg, 0.0870 mmol) in methanol (10 mL) was heated at reflux with dimethylsulfoxide (6.5 LL, 0.095 mmol) for 3 hours. The pale yellow solution was allowed to cool to room temperature, and the solvent removed in vacuo. The product was washed with pentane (2 10 mL) and dried in vacuo. Yield 42.8 mg (87.0%, 0.0613 mmol of [RuCl(dmso-¾(K3-c 5- tach)(PPh3)]Cl.H20.½(C2¾SO)).
NMR Spectroscopy
Figure imgf000065_0003
*H NMR (CD3OD, 399.8 MHz, 293K) δ 7.93 (m, 6H, PPA3, Ar2), 7.50 (m, 9H, PPfa, Ar3 + Ar4), 5.10 (d, 1H, HH = 10.9 Hz, NH2, N1), 4.38 (d, 1H, VHH = 12.2 Hz, NH2, N2), 4.03 (d, 1H, HH = 10.9 Hz, NH2, N1), 3.77 (d, 1H, HH = 12.2 Hz, NH2, N2), 3.65 (d, 1H, HH = 1 1.5 Hz, N¾, N3), 3.49 (m, 1H, CH, Cy1), 3.20 (m, 4H: 3H, W
(C¾)2SO, So1; IH, CH, Cy3), 2.69 (m, 4Η: 3Η, (C¾)2SO, So2; 1Η, CH, Cy2), 2.09 (d, 2JHH = 15.2 Hz, IH, CH2, Cy6), 1.98 (d, HH = 15.2 Hz, IH, CH2, Cy6), 1.82 (m, 2Η, CH2, Cy4), 1.72 (m, 1Η CH2, Cy5), 1.34 (m, 3Η: 1Η, CH2, Cy5; 1Η, NH2, N3); 31P{*H} NMR (CD3OD, 161.8 MHz, 293K) δ 48.8 (s, IP, Ph3).
I3C NMR (CD3OD, 399.8 MHz, 293K) δ 134.65 (d, VPC = 39.5 Hz, ?P 3, Ar1), 134.6 (d, 2JPc = 9.5 Hz, ?Ph}, Ar2), 131.6 (d, VPC = 2.5 Hz, P >A3, Ar4), 130.3 (d, 3JPC = 9.5 Hz, P¾ Ar3), 48.9 (s, (CH3)2SO, So2), 45.4 (s, (CH3)2SO, So1), 44.15 (s, CH, Cy3), 44.1 (s, CH, Cy2), 43.8 (s, CH, Cy1), 34.9 (s, CH2, Cy6), 33.8 (s, CH2, Cy4), 33.4 (s, CH2, Cy5).
Mass Spectrometry
ESI-MS: m/z 606.1062 ([RuCl(dmso-SXK3-ci5-tachXPPh3)3+, Calc 606.1046, 100 %).
Elemental Analysis
Found: C 46.48; H 5.87; N 5.92 % Calcd for C26H36Cl2N30PRuS.H20.½(C2H5SO): C 46.44; H 5.87; N 6.02 %.
Synthesis of ruthenium(II) cis-tach complexes from common ruthenium precursor complexes
All chemicals, including tΓisacetonitrile-κ3Λr-η5-cyclopentadienylruthenium(II) hexafluorophosphate were purchased from Sigma-Aldrich UK. Example 7
qs-cyclopeatadieayl(cif~ci ,3,5-triami
hcxafluorophosphate [7][PF6]
Figure imgf000067_0001
Trisacetoratrile-K3N^5-cyclopentadienylmtheruum(II) hexafluorophosphate (4 mg) and c/s-tach (2mg) were taken up in CD2CI2 (0.5 mL) and allowed to mix for 5 minutes. The solution was left to stand for 24 hours, over which crystals formed. NMR Spectroscopy
*H NMR (CD2CI2, 399.8 MHz, 293K) S 3.95 (br. s, 6H, NH2), 3.72 (s, 5H, Cp), 3.54 (br. s, 3H, CH), 1.81 (m, 6H, CH2);
13C NMR (CD2C12, 399.8 MHz, 293K) δ 63.4 (s, Cp), 43.5 (s, CH), 34.6 (s, CH2).
Example 8
ChIorobis(dimettaylsulfoxide-KS)(m-m-l,3,5^^
rutheniumin) chloride [8] [CI]
([RuC](dmso)2(tach)]C])
Figure imgf000068_0001
Cw,cw-l,3,5-triaminocyclohexane (65.0 mg, 0.503 mmol) was added to a solution of dichloro[/¾c-tris(dimethylsulfoxide-K<^ (243.0 mg, 0.501 mmol) in dimethylsulfoxide (20 mL). The resulting yellow suspension was heated at 130°C for 30 minutes. The pale yellow solution was allowed to cool, and the product was precipitated out by addition of 200 ml of ethyl acetate. The mixture was chilled to -20 °C for 18 hours, forming more precipitate, which was isolated by filtration under reduced pressure, washed with ethyl acetate (2 x 20 mL) and dried in vacuo. Yield: 200.1 mg (92 %, 0.461 mmol of [RuCl(dmso-£)2( 3-cw-tach)]Cl). NMR Spectroscopy
Figure imgf000069_0001
; Cs mirror plane
ln NMR (D20, 399.8 MHz, 293 ): δ 4.52 (d, HH = 11.6 Hz, 2H, NH2, N2), 4.23 (d, VHH = 11.6 HZ, 2H, NH2, N2), 3.88 (s, 2H, NH2, N1), 3.53 (s, 2Η, CH, C2), 3.36 (s, 6Η, (CH3)2SO), 3.27 (s, 1Η, CH, Cy1), 2.14 (d, VHH = 15.5 Hz, 1H, CH2, Cy4), 2.07 (d, HH = 15.5 Hz, 2H, CH2, Cy3), 2.04 (d, VHH = 15.5 Hz, 1H, CH2, Cy4), 1.84 (d, 2JHH=15.5Hz, 2H,CH2, Cy3);
13C{'H} NMR (D20100.5 MHz, 293K): δ 44.2 (s, (CH3)2SO), 43.1 (s, CH, Cy1), 42.4 (s, CH, Cy2), 33.4 (s, CH2, Cy4), 32.5 (s, CH2, Cy3). Mass Spectrometry ESI-MS: m/z 422.0271 ([RuCl(dmso-5)2(^4 "cw-tach)]+, Calc 422.0269, 100 %).
Elemental Analysis
#H20 C/% H/% N/%
Found 26.33 5.83 8.96
0 26.26 5.95 9.19
Table 0.4: CHN Elemental analysis for [RuCl(dmso-^2( -cw-tach)]CI, C10H27ClN3O2RuS2. Example 9
Chloro(η4-l,5-c clooctadiene)(m-c«^-l,3,5-triaminocyclohe ane-κ3 V, V,,N',) ruthenium(II) hexafluorophosphate [9][PF6]
Figure imgf000070_0001
A solution of wer-tris(acetomtrile)chloro^4-l,5-cyclooctadiene)ruthenium(II) hexafluorophosphate (51.3 mg, 0.100 mmol) and cis,c/s-l,3,5-triaminocyclohexane (13.0 mg, 0.101 mmol) in deoxygenated ethanol (10 mL) was heated at reflux for 2 hours. The orange solution was allowed to cool to room temperature, and the volume reduced by half in vacuo and diethyl ether (30 mL) added. The resulting precipitate was collected by filtration and washed with diethyl ether (2 x 10 mL) and dried in vacuo. Yield: 35.0 mg (63.7%, 0.0637 mmol of pluCl(n4-COD)(K3-cw-tach)][PF6]) NMR Spectroscopy
Figure imgf000070_0002
; Cs mirror plane
*H NMR (CD3OD, 399.8 MHz, 293K) δ 5.13 (s, 2H, NH2, N1), 4.20 (d, 2Η, *½_ = 11.2 Hz, NH2, N2), 3.97 (m, 2H, COD-CH), 3.73 (m, 4Η: 2Η, COD-CH; 2Η, NH2, N2), 3.36 (s, 2H, CH, Cy2), 3.18 (m, 1Η, CH, Cy1), 2.50 (m, 2Η, COD-CH2), 2.35 (m, 2Η, COD-CH2), 2.16 (m, 2Η, CH2, Cy3), 2.03 (m, 6Η: 2Η, CH2, Cy4; 4Η, COD-CH2), 1.89 (d, 2Η, HH = 14.9 Hz, CH2, Cy3);
l3C{lR] MR (CD3OD, 100.5 Hz, 293K): 91.7 (s, COD-CH), 88.4 (s, COD-CH), 43.6 (s, CH, Cy2), 43.4 (s, CH, Cy1), 34.0 (s, CH2, Cy3), 33.5 (s, CH2, Cy4), 31.1 (s, COD-C¾), 29.5 (s, COD-CH2).
Mass S ectrometry
ESI-MS: m/z 374.0937 ([RuCl(V"COD)(K3-c/s-tach)]+, Calc 374.0932, 100 %), 169.5588 ([Ru^4"COD)( 3-c«-tach)]+, 169.5624, 25).
Synthesis of ruthenium (Π) cis-tach complexes with nitrogen donor ligands
Example 10
2,2'-Bipyridine-K2JV,N,-dimethylsulfoxide-KS-(^^^
K3JV,JV',N")ruthenium(II) chloride [10][C112
Figure imgf000071_0001
I8]IC1] (45.7 mg, 0.0999 mmol) and 2,2'-bipyridine (18.7 mg, 0.120 mmol) were heated at 120°C in water (5 mL) for 20 minutes, resulting in a deep red solution. Once cooled, the solution was washed with dichloromethane (3 10 mL) and dried in vacuo. The residue was dissolved in methanol (5 mL) and dried in vacuo, giving an orange solid. Yield: 42.7 mg (79.7 %, 0.0797 mmol of [Ru(K2-bipyXdmso-S)(K3-cw- tach)]2Cl).
NMR Spectroscopy
Figure imgf000072_0001
Cs mirror plane
1H NMR (D20, 399.8 MHz, 293K) δ 8.95 (dd, VHH = 5.8 Hz, VHH = 1-2, 2H, bipy, Py6), 8.43 (dd, VHH = 8.3 Hz, VHH = 1.3, 2H, bipy, Py3), 8.14 (td, 3/HH = 7.8 Hz, VHH = 1.2, 2H, bipy, Py4), 7.70 (ddd, VHH = 7.8 Hz, 3JHH = 5.8 Hz, VHH = 1.3, 2H, bipy, Py5), 4.33 (d, HH = 12.5 Hz, 2H, NH2, N2), 4.16 (d, VHH = 12.5 Hz, 2H, NH2, N2), 4.01 (s, 2Η, NH2, N1), 3.49 (s, 2Η, CH, Cy2), 3.24 (s, 1Η, CH, Cy1), 2.63 (s, 6Η, (CHj)2SO), 2.03 (m, 3Η, CH2; 2Η Cy3 + 1Η Cy4), 1.83 (m, 3Η, CH2; 2Η Cy3 + 1Η
Cy4);
t3C{lB) NMR (DA 100.5 MHz, 293K) δ 157.7 (s, bipy, Py2), 151.5 (s, bipy, Py6), 138.6 (s, bipy, Py4), 127.3 (s, bipy, Py5), 125.5 (s, bipy, Py3), 43.5 (s, CH, Cy2), 43.1 (s, (C¾)2SO), 42.0 (s, CH, Cy1), 33.2 (s, CH2, Cy4), 32.8 (s, CH2, Cy3).
Mass Spectrometry
ESI-MS: m z 232.5573 (fRu(K -bipy)(dmso-5)(K3-^-tach)]2+, Calc 232,5568, 100 %), 464.1064 ([Ru( 2-bipyXdmso-5)(K3-cw-tach)]+, 464.1056, 5). Infra-Red Spectroscopy
ATR-IR: 3383, 3211, 3101, 2919, 1602, 1444, 1369, 1226, 1127, 1066, 1050, 1015, 910.
Example 11
Dimethylsulfoxide-icS'-1 ^phenanthroline-K2N,Ar'-(c s-cis-l^,5- triaminocyclohexane-^iVjA^'N'^rutheniuinill) chloride [11][C1]2
(lRuCl(dmso)(phen)(tach)]Cl)
Figure imgf000073_0001
[8][C1] (45.8 mg, 0.100 mmol) and 1,10-phenanthroline (21.6 mg, 0.120 mmol) were heated at 120°C in water (5 mL) for 20 minutes, resulting in a deep red solution. Once cooled, the solution was washed with dichloromethane (3 x 10 mL) and dried in vacuo. The residue was dissolved in methanol (5 mL) and dried in vacuo, giving an orange solid. Yield. 35.9 mg (64.1 %, 0.641 mmol of [Ru(dmso-S)(K2-phen)(K3-cw- tach)]2CI). NMR Spectroscopy
Figure imgf000074_0001
Cs mirror plane
*H NMR (D20, 399.8 MHz, 293K) δ 9.36 (dd, HH = 5.3 Hz, HH = 1.1, 2H, phen, Py6), 8.71 (dd, VHH = 8-25 Hz, HH = 1.1, 2H, phen, Py4), 8.16 (s, 2H, phen, Py7), 8.03 (dd, VHH = 8-25 Hz, VHH = 5.3, 2H, phen, Py5), 4.54 (d, VHH = 12.4 Hz, 2H, NH2, N2), 4.31 (d, HH = 12.4 Hz, 2H, NH2, N2), 3.90 (s, 2H, NH2, N1), 3.55 (s, 2Η, CH, Cy2), 3.20 (s, 1Η, CH, Cy1), 2.52 (s, 6Η, (CH3)2SO), 2.07 (m, 3Η, CH2; 2Η Cy3 + 1Η Cy4), 1.89 (m, 3Η, CH2; 2Η Cy3 + 1Η Cy4);
13C{*H} NMR (D20, 100.5 MHz, 293K) <5 152.3 (s, phen, Py6), 148.2 (s, phen, Py2), 137.9 (s, phen, Py4), 131.2 (s, phen, Py3), 128.0 (s, phen, Py7), 125.6 (s, phen, Py5), 43.5 (s, CH, Cy2), 42.9 (s, (CH3)2SO), 42.0 (s, CH, Cy1), 33.2 (s, CH2, Cy4), 32.9 (s, CH2, Cy3).
Mass Spectrometry
ESI-MS: mJz 244.5570 ([Ru(dmso-S)(K2-phen)(K3-c/i-tach)]2+, Calcd 244.5565, 100%).
Infra-Red Spectroscopy
ATR-IR: 3374, 3251, 4149, 2922, 1602, 1432, 1226, 1126, 1016, 912. Elemental Analysis
#H20 H/% N / %
Found 40.79 5.55 11.29
0 42.93 5.22 12.52
1 41.59 5.41 12.13
2 40.34 5.58 11.75
Table 0.5: CHN Elemental analysis for [RuCl(dmso-S)( 2-phen)(K3-ci5-tach)]Cl, C2oH29Cl2N5ORuS2.
Example 12
Dimethylsulfoxide-KS-l,2-diaminoethane-K2N^
cyclohexane-K^N'^' rutheniumill) chloride [12][C1]2 [Ru(dmso-S)(en)(c s-tach)](Cl)2
Figure imgf000075_0001
[8][CI] (45.8 mg, 0.100 mmol) and 1,2-diaminoethane (7.2 mg, 8.0 uL, 0.12 mmol) were heated at 120°C in water (5 mL) for 20 minutes, resulting in a deep red solution. Once cooled, the solution was washed with dichloromethane (3 10 mL) and dried in vacuo. The residue was dissolved in methanol (5 mL) and dried in vacuo, giving an orange solid. Yield: 29.7 mg (67.6 %, 0.0676 mmol of [Ru(dmso-S (K2-en)(x3-cis- tach)]2Cl) NMR Spectroscopy
Figure imgf000076_0001
Cs mirror plane
1H NMR (D20, 399.8 MHz, 293K) δ 4.66 (s, 2H, NH2, N1), 4.10 (d, HH = 12.0 Hz, 2H, NH2, N2), 3.71 (s, 1Η, CH, Cy1), 3.60 (d, 2Η, HH = 11.1 HZ, en-NH2), 3.48 (d, 2Η, VHH = Π.1 Hz, en-NH2), 3.37 (d, HH = 12.0 Hz, 2H, NH2, N2), 3.34 (s, 6Η, (CH3)2SO), 3.31 (s, 2Η, CH, Cy2), 2.52 (s, 2Η, en-CH2), 2.07 (d, VHH = 15.2 Hz, 2H, CH2, Cy3), 1.95 (d, VHH = 15.2 Hz, 2H, CH2, Cy3), 1.91 (d, VHH = 15.4 Hz, 2H, CH2, Cy4), 1.57 (d, VHH = 15.4 Hz, 2H, CH2, Cy4);
"Ci'H} NMR (CD3OD, 100.5 MHz, 293K) δ 45.3 (s, 6H, (CH3)2SO), 44.6 (s, en- CH2), 43.2 (s, CH, C1), 42.9 (s, CH, C2), 33.1 (s, CH2, C3), 32.6 (s, CH2, C4).
Mass Spectrometry
ESI-MS: /z 184.5553 ([Ru(dmso-S)(K2-en)(K3-cw-tach)]2+, Calcd 184.5568, 100 %), 368.1045 ([Ru(dmso-5)(K2-en)(K3-cw-tach)]+, 368.1057, 5).
Example 13
Figure imgf000077_0001
chloride [13](C1]2
Figure imgf000077_0002
All synthetic procedures were performed under deoxygenated conditions with an argon atmosphere. [8] [CI] (25.0 mg, 0.547 mmol) was taken up in the minimum volume of water (~ '/∑ mL), and acetonitrile (7 mL) added. The solution was heated under reflux for 6 hours and the solvent removed in vacuo. The residue was taken up in the minimum volume of methanol, and addition of diethyl ether (50 mL) resulted in precipitation of the product, which was collected by filtration and dried in vacuo. Yield: 15.9 mg (68.5 % of
Figure imgf000077_0003
NMR Spectroscopy
*H NMR (D20, 399.8 MHz, 293K) δ 3.91 (s, 6H, NH2), 3.30 (s, 3Η, CH), 2.41 (s, 9Η, CH3CN), 1.92 (d, m = 15.2 Hz, 3H, CH2), 1.70 (d, 2 ¾ = 15.2 Hz, 3H, CH2);
uC{lB) NMR (DA 100.5 MHz, 293K) δ 123.9 (s, CH3CN), 42.9 (s, CH), 32.7 (s, CH2), 3.2 ( H3CN).
Mass Spectrometry
ESI-MS: m/z 348.1 ([RuCl(NCMe)2( 3-c«-tach)]2+), 177.1 ([Ru(NCMe)3(K3-c«- tach)]24), 165.5 ([Ru(NCMe)2(K3-c s-tach)(H20)]2+), 156.6 ([Ru(NCMe)2(K3-cis- tach)]2+), 145.1 ([Ru(NCMe)(K3-cw-tach)(H20)]2+). Infra-Red Spectroscopy
ATR-IR: 3345, 3221, 3168, 3118, 2911, 2266 (ON), 1619, 1365, 1228, 1185, 1129, 1033, 916.
Synthesis of ruthenium (Π) cis-tach complexes with chelating diphosphines
All chemicals were purchased from Sigma-Aldrich UK, except methylenebis(diphenylphosphane) (Acros Organics), propane- 1,3- diylbis(diphenylphosphane) (Strem Chemicals) and butane-1,4- diylbis(diphenylphosphane) (Lancaster Synthesis),
Example 14
Chloro[methylenebis(diphenylphosphane-K2JVP ')] (cis,cis-\ ,3,5- triam ocyclohexane-K3jVJV',JV' ')ruthenium(II) chloride— hydrate [14] [CI] ([RuCl(dppm)(tach)]Cl)
Figure imgf000078_0001
A solution of [8][C1] (50.1 mg, 0.109 mmol) in methanol (10 mL) was heated under reflux with methylenebis(diphenylphosphane) (76.9 mg, 0.200 mmol) for 18 hours. The solution was filtered to remove unreacted phosphine, and the solvent removed in vacuo. The residue was taken up in dichloromethane (1 mL), followed by addition of diethyl ether (10 mL), resulting in precipitation. The product was collected by filtration, and the process repeated. The pale cream product was dried in vacuo. Yield: 41.0 mg (52.8 %, 0.0575 mmol of [RuCl(K2-dppm)(K3-cw-tach)]Cl. l ½H20). NMR Spectroscopy
Figure imgf000079_0001
ane
lU NMR (CD3OD, 500.23 MHz, 300K) 3 7.74 (dd, VHP = 1 1.5 Hz, VHH = 7.5 Hz, VHH = 1 5 Hz, 4H, VPh2, Ar2a), 7.67 (dd, HP = 11.5 Hz, VHH = 7.5 Hz, VHH = 1.5 Hz, 4H, YPh2, Ar2b), 7.50 (t, VHH = 7.5 Hz, 4H, PPA2, .Ar5"), 7.43 (t, HH = 7.5 Hz, VHH = 1.5 Hz, 2H, ?P 2, Ar4a), 7.34 (m, 6H, P A2, Ar3b + Ar4 ), 5.79 (dt, VHH = 15.8 Hz, VHP = 10.6 Hz, 1H, PCH2, Br1), 5.17 (d, VHH = 11.0 Hz, 2H, NH2, N2), 3.99 (dt, VHH = 15.8 Hz, VHP = 11.4 Hz, 1H, PCH2, Br1), 3.72 (d, VRH = 11.0 HZ, 2H, NH2, N2), 3.60 (s, 2Η, CH, Cy2), 2.95 (s, 1Η, CH, Cy1), 2.30 (d, HH = 14.9 Hz, 1H, CH2> Cy4), 2.28 (s, 2H NHa, Cy2), 2.17 (d, VHH = 14.9 Hz, 1H, CH2, Cy4), 1.95 (d, VHH = 14.9 Hz, 2H, CH2, Cy3), 1.72 (d, VHH = 14.9 Hz, 2H, CH2, C3);
"P^H} NMR (CD3OD, 202.5 MHz, 295K) δ 10.1 (s, 2P, PPh2);
130{Ή} NMR (CD3OD, 125.8 MHz, 295K) δ 136.12 (vt, | VPC + VP C| = 40 Hz, ?Ph2, ArIb), 133.9 (vt, |VPC + VP>C| = 10 Hz, VPh2, Ar2"), 133,4 (vt, ( PC + VP.C| = 33 Hz, ?Ph2, Arla), 132.2 (vt, |VPC + VP>C] = 10 Hz, ?Ph2, Ar2a), 131.2 (s, ?Ph2, Ar4a), 131.1 (s, PP/22, Ar4b), 130.8 (vt, | VPC + VP.C| = 9 Hz, ?Ph2, Ar3a), 129.1 (vt, | VPC + VP.C| = 9 Hz, ?Ph2, Ar3b), 48.7 (m, PC¾ Br1), 44.8 (s, CB, C2), 44.7 (s, CH, C1), 35.5 (s, C4), 34.7 (s, H2, C3). Mass Spectrometry
ESI-MS: m/z 650.1213 (fRuCl( 2-dppm)( 3-cw-tach)]+, Calc 650.1194, 100 %). Elemental Analysis
# H20 C / % H / % N / %
Found 52.40 5.26 5.85
0 54.31 5.44 6.13
1 52.92 5.59 5.97
1.5 52.25 5.66 5.89
2 51.60 5.73 5.82
Table 0.6: CHN Elemental analysis for [RuCl(K2-dppm)( 3-c/i-tach)]Cl> C31H37N3P2Cl2Ru, calculated with varying water content.
Integrations of the Ή NMR spectrum recorded in anhydrous CD2C12 indicates approximately 1.4 - 2 equivalents of water present, based on various spectra recorded.
Example 15
Chloro[ethane-l,2-diylbis(diphenylphosphane-K2P^^](ci$,cii-l,3,5- triaminocyclohexane-K3N,jV',JV")rutheniuni(II) chloride— hydrate [15][C1] ([RuCl(dppe)(tach)]Cl)
Figure imgf000080_0001
A solution of [8][C1] (50.0 mg, 0.109 mmol) in methanol (10 mL) was heated under reflux with ethane- l,2-diylbis(diphenylphosphane) (85.0 mg, 0.213 mmol) for 18 hours. The solution was filtered to remove unreacted phosphine, and the solvent removed in vacuo. Ethanol (1 mL) was added to the residue, followed by diethyl ether (10 mL) and the product collected by filtration, and the process repeated. The pale cream product was dried in vacuo. Yield: 76.6 mg (93.2 %, 0.102 mmol of [RuCl(K -dppeXK3-cw-tach)]C1.3H20)
NMR Spectroscopy
Figure imgf000081_0001
Cs mirror plane
Ή NMR (CD3OD, 500.2 MHz, 295K) δ 7.87 (ddd, 4H, VHP = 8.8 Hz, VHH = 7.5 HZ, VHH = 1 2 Hz, ?Ph2, Ar22), 7.48 (t, 4H, VHH = 7.7 Hz, PPh2, Ar3b), 7.43 (m, 8H, P ¾, A b + Ar4a + Ar4b), 7.30 (td, 4H, VHH = 7.5 Hz, VHH = 1.2 Hz, PPh2, Ar3a), 4.82 (d, HH = Π.5 Hz, 2H, NH2, N2), 3.98 (d, HH = 11.5 Hz, 2H, NH2, N2), 3.58 (br. s, 2H, CH, Cy2), 3.06 (m,∑JHH,HP = 61.3 Hz, VHH = 16.1 Hz, VHH = 7.7 Hz, 2H, PCH2, Br1), 2.55 (s, 1H, CH, Cy1), 2.38 (m,∑JH¾Hp = 60.0 Hz, VHH = 16.1 HZ, VHH = 7.7 Hz, 2H, PG¾, Br1), 2.30 (d, VHH = 15.8 Hz, 1H, CH2, Cy4), 2.10 (d, HH = 15.8 Hz, 1H, CH2, Cy4), 1.76 (d, VHH = 15.4 Hz, 2H, CH2, Cy3), 1.38 (d, VHH = 15.4 Hz, 2H, CH2, Cy3), 1.14 (s, 2H NH2, N1);
31Ρ{*Η} NMR (CD3OD, 202.5 MHz, 295K) δ 78.3 (s, 2P, P? 2);
"Ci'HJ NMR (CD3OD, 125.8 MHz, 2950K) δ 136.2 (d, |VPC + VP>C| = 40 Hz, ?Ph2, Ai ), 135.6 (vquint, |VPC + 4J C| = 20 Hz, P/¾ Ar2"), 135.3 (d, | VPC + VP>C| = 40 Hz, ?Ph2, ArIb), 132.1 (s, ?Ph2, Ar4a), 131.3 (s, Wh2, Ar b), 130.9 (vquint, |VPC + pcl = 20 Hz, Pi¾, Ar215), 130.7 (vquint, |VPC + VFC| = 20 Hz, PP/¾, Ar3b), 129.2 (vquin , |3JPC + 5JP > C| = 20 Hz, ?Ph2, Ar3a), 44.6 (s, CH, Cy2), 44.0 (s, CH, Cy1), 35.5 (s, CH2, Cy3), 34.3 (s, CH2, Cy4), 29.7 (m, |2JPC + 4JP.C| = 45 Hz, PCH2, Br1). Mass Spectrometry
ESI-MS: Jz 664.1356 ([RuCl( 2-dppe)( 3-cw-tach)]+, Calc 664.1351, 100 %). Elemental Analysis
C / % H / % N / %
Found 50.88 5.66 5.65
0 54.94 5.62 6.01
1 53.56 5.76 5.85
2 52.25 5.89 5.71
3 50.99 6.02 5.58
Table 0.7: CHN Elemental analysis for [RuCl( 2-dppe)(fc3-c s-tach)]Cl, C32H39N3P2Cl2Ru, calculated with varying water content.
Integrations of the 1H NMR spectrum recorded in anhydrous CD2CI2 indicates approximately 3 equivalents of water present.
Example 16
Chlorol ropane-l^-di lbisidiphen lphosphane-K^ li^cw-l^jS- triaminocyclohexane-K3iV,JV',iV' ')ruthenium(n) chloride— hydrate {16] [CI] ([RuCl(dppp)(tach)]Cl)
Figure imgf000082_0001
A solution of [8] [CI] (53.9 mg, 0.117 mmol) in methanol (10 mL) was heated under reflux with propane- 1, 3 -diylbis(diphenyIphosphane) (97.3 mg, 0.236 mmol) for 18 hours. The solvent was removed in vacuo, recrystallised three times in dichloromethane/diethyl ether, collected by filtration and the pale cream product dried in vacuo. Yield: 60.1 mg (68.5 %, 0.0802 mmol of [RuCl(i 2-dppp)(K3-cw- tach)]C1.2H20).
NMR Spectroscopy
Figure imgf000083_0001
lane
*H NMR (CD3OD, 500.2 MHz, 295K) <5 7.66 (br. s, 4H, ?Ph2, Ar2b), 7.54 (t, HH = 7.5 Hz, 2H, P/>/¾, Ar4a), 7.47 (m, 6H, PP 2, Ar4b + Ar3b), 7.44 (t, VHH = 7.5 Hz, 4H, VPh2, Ar3a), 7. 12 (app. t, VRP = 9.2 Hz, VHH = 7.5 Hz, 4H, PPh2, Ar28), 3.61 (d, 2H, VHH = 11.8 Hz, NH2, N2), 3.29 (s, 2H, C , Cy2), 3.20 (d, 2H, HH = Π .8 Hz, NH2, N2), 3.02 (s, 1Η, CH Cy1), 2.82 (m, 2Η, PCH2, Br1), 2.80 (s, 2Η NH2, N1), 2.34 (m, 2Η, PCH2 Br1), 2.28 (m, 1Η, PC¾C/¼, Br2), 2.00 (d, 1Η, HH = 15.0 Hz, CH2, Cy4), 1.90 (d, 1H, VHH = 15.0 Hz, C¾, Cy4), 1.83 (d, 2H, VHH = 15.3 Hz, CH2, Cy3), 1.74 (d, 2H, VHH = 1 .3 Hz, CH2, Cy3), 1.60 (m,
Figure imgf000083_0002
3.6 Hz, 1H, PCH2CH2, Br2);
31P{XH} NMR (CD3OD, 202.5 MHz, 295K) δ 44.0 (s, 2P, Ρη2);
¾Ή} NMR (CDjOD, 125.8 MHz, 2950K) <5 136.4 (t, ) pc + VP>C| = 37 Hz, Ρ^Α2, Arla), 134.5 (t, |VPC + VP.C| = 35 Hz, VPh2, Arlb), 134.3 (t, |Vrc + VP>C| = Hz, P/V¾, Ar29), 133.7 (t, |VPC + 4JP>c| = 4 Hz, ?Ph2, Ar b), 131.4 (s, P/¾, Ar4a), 130.9 (s, PPh2, Ar4b), 130.5 (t, |Vpc + VP.C| = 8. Hz, VPh2, Ar3a), 129.9 (t, |VPC + VFC| = 8.5 Hz, VPh2, Ar3b), 44.5 (s, CH, Cy2), 44.3 (s, CH, Cy1), 35.2 (s, C¾, Cy4), 34.4 (s, Cy3), 29.3 (t, I'JPc + 3JP.C1 = 35 Hz, PC¾, Br1), 20.9 (s, PCH2CH2, Br2). Mass Spectrometry
ESI-MS: w 678.1505 ([RuCl(K2-dppp)(K3-cw-tach)]+, Calc 678.1508, 100 %). Elemental Analysis
# H20 c / % H / % N / %
Found 52.65 5.80 5.39
0 54.78 5.89 5.99
1 53.41 6.02 5.84
2 52.87 6.05 5.61
Table 0.8: CHN Elemental analysis for [RuCl(K2-dppp)(K3-cis-tach)]Cl, C33H i 3P2Cl2Ru, calculated with varying water content.
Integrations of the 1H NMR spectrum recorded in anhydrous CD2C12 indicates approximately 2.2 equivalents of water present.
Example 17
Chloro[butane-l,4-diylbis(diphenylphosphane-K2 , ^l(c«,ci.f-l,3,5- triaminocyclohexane-K^iV^N^^rutheniumin) chloride— hydrate [17] [CI] ([RuCl(dppb)(tach)]Cl)
Figure imgf000084_0001
A solution of f8}[Cl) (50.0 mg, 0.109 mmol) in methanol (10 mL) was heated under reflux with butane- l,4-diylbis(diphenylphosphane) (90.1 mg, 0.211 mmol) for 18 hours. The solvent was removed in vacuo, and the residue recrystallised twice in dichloromethane/diethyl ether, and the product was dried in vacuo. Yield: 45.2 mg (54.9 %, 0.0599 mmol of [RuCl(K2-dppb)(K3-cw-tach)]Cl.l½H20).
NMR Spectroscopy
Figure imgf000085_0001
Cs mirror plane
*H NMR (CD3OD, 500.2 MHz, 295K) δ 7.67 (ddd, 3Jjjp = 12.0 Hz HH = 7.3, HH = 1.5, 4H, ?Ph2, Ar28), 7.61 (m, 6H, PPh2, Ar3b + Ar4b), 7.47 (m, 3JHP = 9.6 Hz VHH = 7.0, HH = 1 5, 4H, PPh2, Ar25), 7.42 (m, 6H, ?Ph2, Ar3a + Ar4a), 3.70 (d, 2H, HH = 11.8 Hz, NH2, N2), 3.33 (d, 2Η, HH = 11 8 HZ, NH2, N2), 3.21 (m, 4Η: 2Η, CH, Cy2; 2Η, PCH2, Br1), 2.65 (s, 1Η, CH, Cy1), 2.55 (s, 2Η, NH2, N1), 2.34 (m,∑JH¾HP = 30.5 Hz, VHH = 13.6, VHH = 5.3, PCH2, Br1), 2.00 (d, 1Η, VHH = 15.0 Hz, CH2, Cy4), 1.93 (m, 2H, PCH2CH2, Br2), 1.88 (d, 1Η, VHH = 15.0 Hz, CH2, Cy4), 1.67 (d, 2H, VHH = 15.0 Hz, CH2, Cy3), 1.49 (d, 2Η, VHH = 15.0 Hz, CH2, Cy3), 1.35 (vquint,∑JHH,HP = 49.0 Hz, VHH = VHH = 12.0, 2H, PCH2CH2, Br2);
31P{XH} NMR (CD3OD, 202.5 MHz, 295K) δ 46.8 (s, 2P, PPh2);
13C{lH] NMR (CD3OD, 125.8 MHz, 2950K) δ 139.1 (t, |VPC + VP>C| = 36 Hz, PPh2, Arla), 135.8 (t, |VPC + VP<C| = 34 Hz, P/7¾, Ar]b), 135.0(t, |VPC + 4JFC| = 9 Hz, PPh2, Ar215), 134.4 (t, |VPC + VP.C| = 9 Hz, PPh2, Ar23), 131.8 (s, PPh2, Ar b), 130.8 (s, PPh2, Ar43), 130.1 (t, |VPC + VP-c| = 8 Hz, ?P 2, Ar3b), 129.7 (t, |VPC + VP-c| = 8.5 Hz, PPh2, Ar3a), 44.3 (s, CH, Cy2), 44.0 (s, CH, Cy'), 35.5 (s, C¾, Cy4), 33.6 (s, CH2, Cy3), 33.1 (t, I'JPc + CI = 30 Hz, PCH2, Br1), 23.9 (s, PCH2CH2, Br2). Mass Spectrometry
ESI-MS: m/z 692.1662 ([RuCl(K2-dppb)(K3-m-tach)]+, Calc 692.1665, 100 %). Elemental Analysis
C / % H / % N / %
Found 54.16 6.01 5.84
0 56.12 5.96 5.77
1 54.77 6.08 5.64
1.5 54.11 6.14 5.56
2 54.47 6.20 5.50
Table 0.9: CHN Elemental analysis for [RuCl( 2-dppb)(K3-m-tach)]Cl, C34H43 3P2Cl2Ru, calculated with varying water content.
Integrations of the Ή NMR spectrum recorded in anhydrous CD2C12 indicates approximately 1.5 equivalents of water present.
Example 18
ChloroK^-eth lene-l^-bisidiphenylphosphane-K^ licis.cis-ljSjS- triaminocyclohexane-K^JVjiV^rutheniumill) chloride— hydrate [18] [CI] ([RuCl(dppv)(tach)]Cl)
Figure imgf000086_0001
A solution of [8] [CI] (50.0 mg, 0.109 mmol) in methanol (5 mL) was heated under reflux with (Z)-ethylene-l,2-bis(diphenylphosphane) (80.0 mg, 0.202 mmol) under an argon atmosphere for 24 hours, resulting in an orange solution. The solution was allowed to cool, the insoluble phosphine was removed by filtration, and diethyl ether (50 mL) added, forming a pale yellow precipitate. The product was collected by filtration and dried in vacuo. Yield: 39.5 mg (50. 1 %, 0.0545 mmol of [RUC^K2- dppv)(K3-m-tach)]Cl.H20).
NMR Spectroscopy
Figure imgf000087_0001
"b" Cs mirror plane
*H NMR (CD3OD, 500.2 MHz, 295K) δ 7.99 (t, VHP = 10.9 Hz, VHH = 7.6, HH = 1.5, 4H, Ρ Ϊ2, Ar23), 7.94 (vd, |2JPH + 3JFH| = 60.7 Hz, 2H, PCH=CHP, Br1), 7.52 (t, VHP = 10.1 Hz, HH = 7.6, HH = L5, 4H, VPh2, Ar2b), 7.47 (t, HH = 7.5 Hz, 4H, ?Ph2, Ar3a), 7.43 (m, 8H, PPh2, Ar3b + Ar4a + Ar4b), 5.17 (d, 2H, HH = 1 1.4 Hz, NH2, N2), 3.99 (d, 2H, VHH = 11.4 HZ, NH2) N2), 3.59 (s, 2H, CH, Cy2), 2.46 (s, 1H, CH, Cy1), 2.32 (d, 1H, VHH = 15.1 HZ, CH,, Cy4), 2.13 (d, 1H, VHH = 15.1 Hz, CH2, Cy4), 1.77 (d, 2H, VHH = 15.0 Hz, CH2, Cy3), 1.40 (d, 2H, VHH = 15.0 Hz, CH2, Cy3), 0.94 (s, 2H, NH2, N1);
31Ρ{*Η} NMR (CD3OD, 202.5 MHz, 295K) c5 76.5 (s, 2P, Ph2);
13C{*H} NMR (CD3OD, 125.8 MHz, 295K) δ 152.4 (vd, |VPC + Vrcl = 69.5 Hz, PCH=CHP, Br1), 136.0 (vquint., |VPC + Vpcl = 18 Hz, ?Ph2, Ar23), 135.7 (vd, |VPc + P'CI = 43 Hz, PP 2, Arla), 133.6 (vd, jVPC + 3JP>cl = 43 Hz, PPh2, Arlb), 132.4 (vquint., |2JPC + 4JP > C| = 17.5 Hz, PP¾, Ar b), 131.5 (s, PPh2, Ar4a), 131.3 (s, PP½, Ar4b), 130.7 (vquint., |3JPC + 5JFC| = 17.5 Hz, PPh , Ar3a), 129.4 (vquint, |3JPC + 5JP.C| = 18 Hz, PPh2, Ar3b), 44.6 (s, CH, Cy2), 44.1 (s, CH, Cy1), 35.6 (s, C¾, Cy4), 34.3 (s, CH2, Cy3).
Mass Spectrometry
ESI-MS: /z 662.1195 ([RuCl(K2-dppv)(K3-cw-tach)]+, Calc 622.1194, 100 %).
Elemental Analysis
# H20 c/ % H / % N / %
Found 53.70 5.48 5.89
0 55.10 5.35 6.02
1 53.71 5.49 5.87
Table 0.10: CHN Elemental analysis for [RuCl(K2-dppv)(K3-«5-tach)]Cl, C32H3 3P2Cl2 u, calculated with varying water content.
Integrations of the 1H NMR spectrum recorded in anhydrous CD2CI2 indicates approximately 1 equivalent of water present.
Example 19
Chloro[phenylene-l,2-bis(diphenylphosphane- 2P,P')](c/-i,m-l,3,5- triaminocyclohexane- ^N'jN' rutheniumill) chloride— hydrate [19][C1]
([RuCl(dppben)(tach)lCl)
Figure imgf000089_0001
A solution of [8][CI] (50.0 mg, 0.109 mmol) in methanol (5 mL) with phenylene-1,2- bis(diphenylphosphane) was heated at 90 °C in sealed ampoule under argon for 48 hours. The deep orange solution was allowed to cool, over which a white precipitate formed. The unreacted phosphine precipitate was removed by filtration and diethyl ether (90 mL) added to the solution, forming a cream precipitate. The mixture was cooled to -20 °C for 2 hours, the product isolated by filtration, and dried in vacuo. Yield: 58.6 mg (68.6 %, 0.0748 mmol of rRuCl(K2-dppben)(K -cis-tach)]C1.2H20). NMR Spectroscopy
Figure imgf000089_0002
b Cs mirror plane lH NMR (CD3OD, 500.2 MHz, 295K) δ
8.07 (ddd, HP = 1 1.0 Hz, HH = 7.5 Hz, HH = 1.2 Hz, 4H, PPh2, Ar211), 7.52 (m, 6H: 2H, PPh2, Ar4a; 4H, PC6H4P, Br2 + Br3), 7.44 (t, VHH = 7.5 HZ, 4H, VPh2, Ar3a), 7.39 (dd, VHH = 7.4 Hz, VHH = 7.2 Hz, 4H, PPhz, Ar3b), 7.34 (td, VHH = 7.2 Hz, HH = 1.4 Hz, 4H, PPh2, Ar b), 7.34 (ddd, VHP = 10.0 Hz, VHH = 7.4 Hz, VHH = 1.4 Hz, 4H, fPh2, Ar4b), 4.93 (d, HH = 11 8 HZ, 2H, NH2, N2), 3.87 (d, HH = Π.8 Hz, 2H, NH2> N2), 3.56 (s, 2Η, CH, Cy2), 2.72 (s, 1Η, CH, Cy1), 2.30 (d, VHH = 15.4 Hz, 1H, CH2, Cy4), 2.14 (d, VHH = 15.4 Hz, 1H, CH2, Cy4), 1.86 (d, HH = 15.2 Hz, 2H, CH2, Cy3), 1.74 (d, VHH = 15.2 Hz, 2H, CH2, Cy3), 1.39 (s, 2H, NH2, N2); 3ίΡ{Ή} NMR (CD3OD 202.5 Hz, 295K) δ 72.9 (s, 2P, Ph2);
"( {¾} NMR (CD3OD, 125.8 MHz, 2950K) δ 145.6 (vt, |VPC + VP C| = 82 Hz, PC6H4P, Br1), 139.9 (t, |VRC + VP>c| = 10 Hz, ?Ph2, Ar2a), 133.6 (m, PP/z2, ArIa + Arlb), 133.5 (t, |VPC + VP¾| = 17 Hz, PC^P, Br2), 133.0 (t, |VPC + VP.C| = 9 Hz, PPki, Ar215), 131.8 (s, PC6¾P, Br3; s, PP/*2, Ar a), 131.1 (s, P A2, Ar4b), 130.5 (t, |VPC + Vp-c| = 9 Hz, VPh2, Ar3 ), 129.5 (t, |VPC + VFC| = 9 Hz, Pi¾, Ar a), 44.7 (s, CH, Cy2), 44.4 (s, CH, Cy1), 35.6 (s, CH2, Cy4), 34.3 (s, CH2, Cy3). Mass Spectrometry
ESI-MS-. m/z 712.1372 ([RuCl(K2-dppben)(K3-cw-tach)]+, Calc 712.1352, 100 %).
Elemental Analysis
# H20 C / % H / % N / %
Found 55.50 5.44 5.33
0 57.83 5.26 5.62
1 56.47 5.40 5.49
2 55.18 5.53 5.36
Table 0.11: CH Elemental analysis for [RuCl(K2-dppben)(K3-cis-tach)]Cl, C36H39N3P2Cl2Ru, calculated with varying water content. 3
Integrations of the 1H NMR spectrum recorded in anhydrous CD2CI2 indicates at least 1 equivalent of water present.
Example 20
Aquofethane-l^-diylbisidiphenylphosphane-K^P')] (ds,m-l,3,5-triamino cyc]ohexane-K3N,JVyV'')rutheniiim(II) bistrifluoromethane sulphonate
(lRu(OH2)(dppe)(m-tach)](OTf)2) A solution of ([RuCl(dppe)(tach)]Cl) (500 μΜ) and silver trifluoromethane sulphonate (silver triflate) (2 equiv) in H20 (25 mL) was stirred for 18 h, shielded from light. The resulting suspension was filtered over celite to remove the insoluble silver chloride. 1,4-dioxane (1 equiv, reference at 6H 3.75) and CD3OD (1.6%) were added to the solution. NMR spectra were recorded on a Bruker Avance AV500 spectrometer at 310 using solvent suppression techniques and CD3OD as deuterium lock.
NMR Spectroscopy
rH NMR (H20, 500.2 MHz, 298K) 6 7.62 (t, J = 8.6 Hz, 4H, ?Ph%\ 7.50 (m, 16H, Wh2), 4.27 (d,2/HH = 12.5 Hz, 2H, NH2, N2*), 3.37 (s, 2Η, CH, Cy2), 3.12 (m, 2Η, PCH2), 2.68 (m, 2Η, PCH2), 2.38 (s, 1Η, CH, Cy1), 2.27 (d, HH = 14.8 Hz, 1H, CH2, Cy4), 2.18(d, 2JHH = 14.8 Hz, 1H, CH2, CI), 1.74 (d, HH = 17.7 Hz, 2H, CH2, Cy3), 1.26 (s, 2Η, H2, N1), 0.99 (d, 2JM = 17.7 Hz, 2H, CH3, Cy3);
31Ρ{*Η} NMR (H20, 202.5 MHz, 295 ) δ 74.6 (s, 2P, Ph2). Integration suppressed and geminal resonance not observed due to solvent suppression technique.
Example 21
Aquoipropane-l^-di l isidiphen lphosphane- ^ ^J^iJjm-ljS-S-triainino cyclohexane- 3NJvyV")ruthenium(II) bistrifluoromethane sulphonate
(lRu(OH2)(dppp)(m-tach)](OTf)2) A solution of ([RuCl(dppp)(tach)JCl) (500 μΜ) and silver trifluoromethane sulphonate (silver inflate) (2 equiv) in H20 (25 mL) was stirred for 18 h, shielded from light. The resulting suspension was filtered over celite to remove the insoluble silver chloride. 1,4-dioxane (1 equiv, reference at δΗ 3.75) and CD3OD (1.6%) were added to the solution. NMR spectra were recorded on a Bruker Avance AV500 spectrometer at 310 K using solvent suppression techniques and CD3OD as deuterium lock.
NMR Spectroscopy
Ή NMR (H20, 500.2 MHz, 298K) δ 7.59 {app q, J = 7.4 Hz, 2H, ?Ph2), 7.54 (d, J = 7.6 Hz, 2H, Wh2), 7.50 (t, J= 7.4 Hz, 8H, Wh2), 7.42 (t, J = 7.6 Hz, 4H, ?Ph2), 7.25 (t, J = 7.4 Hz, 4H, PP/¾), 3.78 (d, HH = 15.3 Hz, NH2, N2), 3.35 (m, 4Η; 2Η, NH2, N2; 2Η CH*, Cy2), 2.90 (s, ΙΗ, CH, Cy1), 2.64 (m, 2Η, PCH2), 2.45 (m, 4Η; 2Η, PCH2; 2Η NH2*, N1), 2.27 (m, 1Η, PCH2CH2), 1.99 (app. s, 2H; CH2, Cy4 1.92 (m, 1H, PCH2CH2), 1.82 (d, HH = 17.5 Hz, 2H, CH2, Cy3), 1.46 (d, 2JHH = 17.5Hz, 2H,CH2, Cy3); 31P{1H} NMR (H20, 202.5 MHz, 295 ) 6 41.7 (s, 2P, />Ph2).
*Unable to unequivocally assign resonances without 'H/I3C 2D correlation spectrum.
Biological Assay
Cell lines and MTT Assay
Cell Culture
The A549 cell line was kindly donated by The Technology Facility, Department of Chemistry, University of York. The A2780 cell line was purchased from the ECACC. Cell cultures were maintained in a 90% humidified atmosphere of C02 at 37 °C. Cell cultures were maintained in DMEM (A549) or RPMI (A2780) supplemented with 2 mM glutamine and 10% Foetal Bovine Serum. Sub-confluent cultures (70-80%) were split at a seeding of 1 :3 to 1 :6 using 0.25% Trypsin/EDTA. Culture medium and FBS were obtained from Invitrogen Gibco and all other materials from Sigma.
The MTT Assay
Cells were seeded at a density of 1,000 cells per well (A549) or 2,500 cells per well (A2780) in 100 uL of their respective culture medium in a 96 well plate, with positive (columns 1 and 11) and negative (columns 2 and 12) controls located at each end of the plate. Positive controls consisted of culture medium with no cells, representative of 100 % inhibition of MTT metabolisation, and negative controls consisted of untreated cells, representative of 0 % inhibition. Cells were allowed to adhere to the plate surface for 24 hours during incubation before addition of drug. 100 of culture medium was added to each control well, and 100 uL of a 2x solution of the compound to be tested in culture medium to the remaining wells. A total of eight concentrations were tested, performed in octuplicate and typically between 300 uM and 0.1 μΜ, with the eight concentrations selected to fall on the dose-response curve for the compound.
The cells were incubated with the drug for 72 hours before addition of 50 μΐ, of MTT (2 mg mL) in PBS and incubation for a further 2 hours, over which the MTT was metabolized to insoluble formazan crystals. The plates were centrifuged at 500g for 10 minutes and 220 uL of the culture medium in each well removed and the formazan solubilised by addition of 150 uL DMSO. The plate was shaken to ensure complete dissolution of the formazan, before absorbance at 540 run recorded using a Hidex Plate Chameleon V plate reader. The value for each concentration of drug was plotted graphically as a percentage of the negative control compared to the positive. The data was fitted using a sigmoidal function and the concentration of drug to cause 50 % reduction of the absorbance compared to control values calculated as the IC50 value. Statistical calculations were performed using Origin v8.5. Experiments were performed in triplicate, and the overall IC50 value calculated as the average of those obtained.
Biological ICsn data for representative complexes of the invention
ICso / μΜ
Complex A549 A2780
cisplatin 2.70 (0.05) 0.43 (0.01)
[RuCl(dmso)(tach)(PPh3)]Cl [6][C1] 194 (4) 67.8 (1.0)
[RuCl(dmso)2(tach)]C! [8]Cl i > 300 > 100
[RuCl(dmso)(phen)(tach)]Cl [11]C1 > 300 n.d.
[RuCl(dppm)(tach)]Cl [14IC1 41.7 (1.0) 12.4 (0.2)
[RuCl(dppe)(tach)]Cl [15][C1] 9.88 (0.04) 3.39 (0.12)
[RuCl(dppp)(tach)]C] [16][C1] 1.02 (0.03) 0.35 (0.01)
[RuCl(dppb)(tach)]Cl I17][C1] 1.15 (0.02) 0.39 (0.01)
[RuCl(dppv)(tach)]Cl [18][C1] 25.1 (0.4) 7.47 (0.17)
[RuCl(dppben)(tach)]Cl tl9][Cl] 2.73 (0.11) 1.14 (0.04)
All numbers include standard deviations in parentheses and are an average of three separate experiments.
Additional Data
General Cell Collection: A549
Catalogue No.: 86012804
Cell Line Name: A549
Keywords: Human Caucasian lung carcinoma
Derived from a 58 year old Caucasian male. The cells can synthesise lecithin utilising the cytidine diphosphocholine
Cell Line Description:
pathway. Occasional cells may also contain inclusion bodies although they are not known to carry any human pathogen.
Species: Human
Tissue: lung
Morphology: Epithelial
Growth Mode: Adherent
Split sub-confluent cultures (70-80%) 1 :3 to 1:6 i.e. seeding
Subculture Routine: at 2-4x10,000 cells/cm2 using 0.25% trypsin or
trypsin EDTA; 5% C02; 37°C.
Ham's F12K or DMEM + 2mM Glutamine + 10% Foetal
Culture Medium:
Bovine Serum (FBS).
Karyotype: Hypotriploid
Products: Lecithin, High amounts of de-saturated fatty acids.
Depositor: Obtained from ATCC
Country: USA
References: J Nat Cancer Inst 1973;51:1417; Int J Cancer 1967;17:62
Source: HPA/ECACC
General Cell Collection: A2780
Catalogue No.: 93112519
Cell Line Name: A2780
Keywords: Human ovarian carcinoma
The A2780 human ovarian cancer cell line was established from tumour tissue from an untreated patient. Cells grow as a monolayer and in suspension in spinner cultures. A2780 is Cell Line Description: the parent line to the cisplatin resistant cell line A2780 cis
(ECACC catalogue no. 93112517) and the adriamycin resistant cell line A2780 ADR (ECACC catalogue no.
93112520).
Species: Human
Tissue: ovary
Morphology: Epithelial
Growth Mode: Adherent
Split sub-confluent cultures (70-80%) 1 :3 to 1:6 i.e. seeding
Subculture Routine: at 3-6xlO,O0Ocells/cm2 using 0.25% trypsin or
trypsin EDTA; 5% C02; 37°C.
RPMI 1640 + 2mM Glutamine + 10% Foetal Bovine Serum
Culture Medium:
(FBS).
Karyotype: Not specified
Dr T H Ward, Cell Culture Unit, Patterson Laboratories,
Depositor:
Christie Hospital, Manchester
Country: UK
References: Semin Oncol 1984;11:285; Cancer Res 1987;47:414
Source: HPA/ECACC
Water Solubility
A full solubility study has not been performed with those complexes tested for cytotoxic activity against tumour cell lines, however all complexes are or least as water soluble as cisplatin (approx. 6 mM). References
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Claims

Claims
1. A complex of formula I:
Figure imgf000101_0001
in which,
R1, R2, R3, R4, R5 and R6, which may be the same or different are each, hydrogen or alkyl CI to 20 alkenyl CI to 20, aryl, alkyl(ci to 20)aryl, alkenyl(ci to 20)aryl, heteroaryl, a sugar, an amino acid, a nucleoside, a nucleotide or a peptide;
R7, R8 and R9, which may be the same or different are each, hydrogen or alkyl CI to 20;
L1, L2 and L3, which may be the same or different, are each selected from the group comprising halogen (halogen may optionally be a bridging moiety between two groups of formula I), -PR10RUR12, -NCR13, -S(0)RuR15, or
a pair of any two of L1, L2 and L3 may comprise a moiety -R15R17N-(CHR18)n-
NR19R20 or -R21R22P-(CHR23)m-PR24R25;
a pair of any two of L1, L2 and L3 may comprise a moiety of formula VI;
Figure imgf000101_0002
a pair of any two of L1, L2 and L3 may comprise a C6 to 20 cycloalkyldiene;
L1, L2 and L3 may together form a 6- to 8- membered arene;
n and m, which may be the same or different, are each an integer 1 to 6
R10. R11 and R12, which may be the same or different, are each alkyl CI to 20 or aryl optionally substituted by one or more alkyl CI to 20;
R", R14 and R15 which may be the same or different, are each alkyl CI to 20 or aryl optionally substituted by one or more alkyl C I to 20;
R16, R17, R18, R] 9, R20, R21, R22, R23, R24 and R25, which may be the same or different, are each alkyl C I to 20 or aryl optionally substituted by one or more alkyl C I to 20; any adjacent pair of R18 or R23 may together form a bond;
R26 and R27, which may be the same or different, are each hydrogen, alkyl CI to 20 or R26 and R27 together form an optionally aromatic ring; and isomers thereof;
in free or in salt form.
2. A complex according to claim 1 wherein R1, R2, R3, R4, R3 and R6, which may be the same or different, are each, hydrogen or alkyl CI to 20, alkenyl CI to 20, aryl, alkyl(ci tO 20)aryl, alkenyl Ci to 20)aryl or heteroaryl. 3. A complex according to any one of claims 1 or 2 wherein a pair of Ll, L2 and L3, represent a moiety -R16R17N-(CHRL8)N-NR19R20 or -R21R22P-(CHR23)M-PR24R25; and R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, m and n, are each as defined in claim 1
4. A complex according to any one of the preceding claims wherein R and are each hydrogen.
5. A complex according to any one of the preceding claims wherein a pair of L1, L2 and L3, represent a moiety -R2 ,R2 P-(CHR23)ffi-PR24R25,
and R21, R22, R23, R24, R25 and m are each as defined in the preceding claims.
6. A complex according to any one of the preceding claims wherein R23 is hydrogen.
7. A complex according to any one of the preceding claims wherein R21, R22, R24 and R25 are each aryl.
8. A complex according to claim 7 wherein R21, R22, R24 and R25 are each phenyl.
9. A complex according to any one of the preceding claims wherein m is an integer from 1 to 4.
10. A complex according to any one of the preceding claims wherein R1, R3 and R5 are each hydrogen.
11. A complex according to any one of the preceding claims wherein R1, R2, R3, R4, R5 and R6 are each hydrogen.
12. A complex according to any one of the preceding claims wherein R7, R8 and R9 are each hydrogen.
13. A complex according to any one of the preceding claims wherein a pair of L1, L2 and L3, represent a moiety of formula VI, R2(S and R27 are preferably the same and may each be hydrogen, to provide a ligand of formula Via, or R26 and R27 together form an aromatic ring, to provide a ligand of formula VIb:
Figure imgf000104_0001
14. A complex according to any one of the preceding claims wherein a pair of L1, L2 and L3, represent a C6 to 20 cycloalkyldiene. 15. A complex according to any one of the preceding claims wherein the counter ion is halide.
16. A complex according to any one of the preceding claims wherein the complex of formula I is selected from the group consisting of:
chloro(cw-cis-l,3,5-triaminocyclohexane-K3N,N',N' ')bis(triphenyl
phosphane)ruthenium(n) hexafluorophosphate;
Figure imgf000104_0002
KSATN'.N' ^triphenylphosphanenithemum^— dichloromethane; μ-chloro-dichloro- 1κ! C ,2K' Cl-[bis(cis-cis- 1 ,3 ,5-triaminocyclohexane)-
Figure imgf000105_0001
tetraphenylborate— dichloromethane;
acetonitrilechloro(m-cw-l ,3,5-triaminocyclohexane-K3N,N',N' ')
triphenylphosphaneruthenium(II) hexafluorophosphate;
bisacetonitrilei^w-c/j-l^jS-triaminocyclohexane-^NN'.N' ')
triphenylphosphaneruthenium(n) hexafluorophosphate,
c orodimethylsulfoxide-K5'-(cw-cw-l,3,5-triaminocyclohexane-K Ν,Ν',Ν") triphenylphosphaneruthenium(n) chloride— hydrate;
^-cyclopentadienyl(m-c/s-l,3,5-triaminocyclohexan
hexafluorophosphate ;
cWorobisidimethylsulfo ide-K^^w-cw-ljSjS-triaminocyclohexane-K^N^N' ') ruthenium(II) chloride;
cWoro^ -l,5-cyclooctadiene)(ci5-cis-l,3,5-triaminocyclohexane-K3N,N',N'') ruthenium(II) hexafluorophosphate;
2,2'-bipyridine-K2N,N'-dimethylsulfoxide-^
K3N,N*,N")ruthenium(II) chloride;
dimethylsulfoxide-xS-l , 10-phenanthroline-K2N,N '-(cis-cis- 1 ,3,5 -triamino
cyclohexane-K3N,N',N' ')ruthenium(II) chloride;
dimethylsulfoxide-KS-l,2-diaminoethane-K2N,^
Figure imgf000105_0002
chloride;
trisacetonitrile(cw-cw-l,3,5-triaminocyclohexane-K Ν,Ν',Ν' ')ruthenium(II) chloride; chloro[methylenebis(diphenylphosphane-K P,P ')](cis, cis- 1 ,3,5-triaminocyclohexane-
Figure imgf000105_0003
')ruthenium(H) chloride— hydrate; chloro [ethane- 1,2-diylbis (diphenylphosphane-K .-P ')] (cw,c«- 1,3,5-triarriino cyclohexane-K3N,N",iV' ')nithenium(II) chloride— hydrate;
chloro [propane- 1,2-diylbis (diphenylphosphane-K2?,/' ')] (cis,cis-l,3,5-triamino cyclohexane-K3N,iV",N' ')ruthenium(H) chloride— hydrate;
chloro [butane- 1,2-diylbis (diphenylphosphane-K2P,/> ')] (cwfcw-1 ,5-triamino cyclohexane- 3JV,N',N' ')ruthenium(II) chloride— hydrate;
chloro [(Z)-ethylene-l,2-bis (diphenylphosphane-K2 , ')] (cw,cw-l,3,5-triamino cyclohexane-K3N,iV",N")ruthenium(II) chloride— hydrate; and
chloro [phenylene-l,2-bis (diphenylphosphane-K2/-*, 3 ')] (cw,cw-l,3,5-triamino cyclohexane- Ν,Ν',Ν' ')ruthenium(II) chloride— hydrate;
aquo [ethane- l,2-diylbis(diphenylphosphane-K2 >,/> ')] (cis,cis- 1,3,5-triamino cyclohexane-K^N'.N' ')ruthenium(II) bistrifluoromethane sulphonate; and aquo [propane- 1 ,3-diylbis(diphenyIphosphane-K2P,/J ')](cis,cis- 1 ,3 ,5-triamino cyclohexane-K3N,N',N' *)ruthenium(II) bistrifluoromethane sulphonate;
and isomers thereof;
in free or in salt form.
A complex according to any one of the preceding claims as a medicament.
18. A complex according to any one of the preceding claims is a medicament for the treatment of a proliferative disorder.
19. A complex according to claim 18 wherein the proliferative disorder comprises one or more of primary cancer, breast cancer, colon cancer, prostate cancer, non-small cell lung cancer, glioblastoma, lymphoma, mesothelioma, liver cancer, intrahepatic bile duct cancer, oesophageal cancer, pancreatic cancer, stomach cancer, laryngeal cancer, brain cancer, ovarian cancer, testicular cancer, cervical cancer, oral cancer, pharyngeal cancer, renal cancer, thyroid cancer, uterine cancer, urinary bladder cancer, hepatocellular carcinoma, thyroid carcinoma, osteosarcoma, small cell lung cancer, leukaemia, myeloma, gastric carcinoma and metastatic cancers.
20. A complex according to any one of claims 18 or 19 wherein the proliferative disorder is a metastatic cancer. 21. The use of a complex of formula I according to claim 1 in the manufacture of a medicament.
22. The use of a complex according to claim 21 wherein the medicament is for the treatment of a proliferative disorder.
23. The use of a complex according to any one of claims 21 or 22 wherein the medicament is in the form of an aqueous solution.
24. A method of treatment or alleviation of a proliferative disorder which comprises administering to a mammal a therapeutically effective amount of a complex of formula I according to claim 1.
25. A method of treatment or alleviation of a proliferative disorder according to claim 24 which comprises preparing an aqueous solution of a complex of formula I according to claim 1.
26. A pharmaceutical composition comprising a complex of formula I according to claim 1, in free form or in pharmaceutically acceptable salt form, in association with a pharmaceutically acceptable adjuvant, diluent or carrier.
27. A pharmaceutical composition comprising a complex of formula I according to claim 1 in free form or in pharmaceutically acceptable salt form, in combination with another therapeutically active ingredient, optionally in association with a pharmaceutically acceptable adjuvant, diluent or carrier.
28. A pharmaceutical composition according to claim 27 wherein the composition is in the form of an aqueous solution.
29. A process for the manufacture of a complex of formula I according to claim 1 which comprises one or more of the following steps;
(a) reacting a compound of formula Π;
Figure imgf000108_0001
Li, L2 and L3 are each as defined in claim 1 ;
L4a, L5a and L6a are each a leaving ligand, such as halo, dmso, etc.; with a compound of formula HI;
Figure imgf000109_0001
in which R1, R2, R3, R4, R5, R6, R7, R8 and R9, are each as defined in claim 1 ; or (b) reacting a complex of formula IV;
Figure imgf000109_0002
in which R1, R2, R3, R4, R5, R6, R7, R8 and R9, are each as defined in claim 1 ; and at least one of Lla, a and L3a is a leaving ligand, selected from the group consisting of halo, dmso and -PR28R29R30;
R28, R29 and R30 , which may be the same or different, are each alkyl CI to 20, aryl (optionally substituted by one or more alkyl CI to 20), amino or -OR31 ,
R31 is hydrogen or alkyl C I to 20; and
the remainder of L\a, L2a and L3a, which may be the same or different, each have the same meaning as L1, L2 and L3 respectively or may be selected from the group consisting of halo, dmso and -PR28R2 R30; with one or more compounds of ligands Li, L2 and L3 wherein Li, L2 and L3 are each as defined in claim I.
30. A complex of formula IV:
Figure imgf000110_0001
in which,
R1, R2, R3, R4, R5 and R6, which may be the same or different are each, hydrogen or alkyl CI to 20, alkenyl CI to 20, aryl, alkyl(Ci to 20)aryl, alkenyl(Ci t020)aryl, heteroaryl, a sugar, an amino acid, a nucleoside, a nucleotide or a peptide;
R7, R8 and R9, which may be the same or different are each, hydrogen or alkyl CI to 20; and
at least one of L]a, L2a and L3a is a leaving ligand, selected from the group consisting of halo, dmso and -PR28R29R30;
R28, R29 and R30, which may be the same or different, are each alkyl CI to 20, aryl (optionally substituted by one or more alkyl CI to 20), amino or -OR31;
R31 is hydrogen or alkyl CI to 20; and
the remainder of Lla, L2a and L3a, which may be the same or different, each have the same meaning as L , L and L respectively or may be selected from the group consisting of halo, dmso and -PR28R29R30;
and isomers thereof; in free or in salt form.
31. A complex, use, method composition or process as hereinbefore described with reference to the accompanying examples.
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